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Viloria Winnett A, Akana R, Shelby N, Davich H, Caldera S, Yamada T, Reyna JRB, Romano AE, Carter AM, Kim MK, Thomson M, Tognazzini C, Feaster M, Goh YY, Chew YC, Ismagilov RF. Daily SARS-CoV-2 Nasal Antigen Tests Miss Infected and Presumably Infectious People Due to Viral Load Differences among Specimen Types. Microbiol Spectr 2023; 11:e0129523. [PMID: 37314333 PMCID: PMC10434058 DOI: 10.1128/spectrum.01295-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/21/2023] [Indexed: 06/15/2023] Open
Abstract
In a recent household transmission study of SARS-CoV-2, we found extreme differences in SARS-CoV-2 viral loads among paired saliva, anterior nares swab (ANS), and oropharyngeal swab specimens collected from the same time point. We hypothesized these differences may hinder low-analytical-sensitivity assays (including antigen rapid diagnostic tests [Ag-RDTs]) by using a single specimen type (e.g., ANS) from reliably detecting infected and infectious individuals. We evaluated daily at-home ANS Ag-RDTs (Quidel QuickVue) in a cross-sectional analysis of 228 individuals and a longitudinal analysis (throughout infection) of 17 individuals enrolled early in the course of infection. Ag-RDT results were compared to reverse transcription-quantitative PCR (RT-qPCR) results and high, presumably infectious viral loads (in each, or any, specimen type). The ANS Ag-RDT correctly detected only 44% of time points from infected individuals on cross-sectional analysis, and this population had an inferred limit of detection of 7.6 × 106 copies/mL. From the longitudinal cohort, daily Ag-RDT clinical sensitivity was very low (<3%) during the early, preinfectious period of the infection. Further, the Ag-RDT detected ≤63% of presumably infectious time points. The poor observed clinical sensitivity of the Ag-RDT was similar to what was predicted based on quantitative ANS viral loads and the inferred limit of detection of the ANS Ag-RDT being evaluated, indicating high-quality self-sampling. Nasal Ag-RDTs, even when used daily, can miss individuals infected with the Omicron variant and even those presumably infectious. Evaluations of Ag-RDTs for detection of infected or infectious individuals should be compared with a composite (multispecimen) infection status to correctly assess performance. IMPORTANCE We reveal three findings from a longitudinal study of daily nasal antigen rapid diagnostic test (Ag-RDT) evaluated against SARS-CoV-2 viral load quantification in three specimen types (saliva, nasal swab, and throat swab) in participants enrolled at the incidence of infection. First, the evaluated Ag-RDT showed low (44%) clinical sensitivity for detecting infected persons at all infection stages. Second, the Ag-RDT poorly detected (≤63%) time points that participants had high and presumably infectious viral loads in at least one specimen type. This poor clinical sensitivity to detect infectious individuals is inconsistent with the commonly held view that daily Ag-RDTs have near-perfect detection of infectious individuals. Third, use of a combination nasal-throat specimen type was inferred by viral loads to significantly improve Ag-RDT performance to detect infectious individuals.
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Affiliation(s)
| | - Reid Akana
- California Institute of Technology, Pasadena, California, USA
| | - Natasha Shelby
- California Institute of Technology, Pasadena, California, USA
| | - Hannah Davich
- California Institute of Technology, Pasadena, California, USA
| | - Saharai Caldera
- California Institute of Technology, Pasadena, California, USA
| | - Taikun Yamada
- Pangea Laboratory LLC, Tustin, California, USA
- Zymo Research Corporation, Irvine, California, USA
| | | | - Anna E. Romano
- California Institute of Technology, Pasadena, California, USA
| | | | - Mi Kyung Kim
- California Institute of Technology, Pasadena, California, USA
| | - Matt Thomson
- California Institute of Technology, Pasadena, California, USA
| | | | - Matthew Feaster
- Pasadena Public Health Department, Pasadena, California, USA
| | - Ying-Ying Goh
- Pasadena Public Health Department, Pasadena, California, USA
| | - Yap Ching Chew
- Pangea Laboratory LLC, Tustin, California, USA
- Zymo Research Corporation, Irvine, California, USA
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Viloria Winnett A, Akana R, Shelby N, Davich H, Caldera S, Yamada T, Reyna JRB, Romano AE, Carter AM, Kim MK, Thomson M, Tognazzini C, Feaster M, Goh YY, Chew YC, Ismagilov RF. Extreme differences in SARS-CoV-2 viral loads among respiratory specimen types during presumed pre-infectious and infectious periods. PNAS Nexus 2023; 2:pgad033. [PMID: 36926220 PMCID: PMC10013338 DOI: 10.1093/pnasnexus/pgad033] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 03/16/2023]
Abstract
SARS-CoV-2 viral-load measurements from a single-specimen type are used to establish diagnostic strategies, interpret clinical-trial results for vaccines and therapeutics, model viral transmission, and understand virus-host interactions. However, measurements from a single-specimen type are implicitly assumed to be representative of other specimen types. We quantified viral-load timecourses from individuals who began daily self-sampling of saliva, anterior-nares (nasal), and oropharyngeal (throat) swabs before or at the incidence of infection with the Omicron variant. Viral loads in different specimen types from the same person at the same timepoint exhibited extreme differences, up to 109 copies/mL. These differences were not due to variation in sample self-collection, which was consistent. For most individuals, longitudinal viral-load timecourses in different specimen types did not correlate. Throat-swab and saliva viral loads began to rise as many as 7 days earlier than nasal-swab viral loads in most individuals, leading to very low clinical sensitivity of nasal swabs during the first days of infection. Individuals frequently exhibited presumably infectious viral loads in one specimen type while viral loads were low or undetectable in other specimen types. Therefore, defining an individual as infectious based on assessment of a single-specimen type underestimates the infectious period, and overestimates the ability of that specimen type to detect infectious individuals. For diagnostic COVID-19 testing, these three single-specimen types have low clinical sensitivity, whereas a combined throat-nasal swab, and assays with high analytical sensitivity, was inferred to have significantly better clinical sensitivity to detect presumed pre-infectious and infectious individuals.
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Affiliation(s)
| | - Reid Akana
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Natasha Shelby
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Hannah Davich
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Saharai Caldera
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Taikun Yamada
- Pangea Laboratory LLC, 14762 Bentley Cir, Tustin, CA 92780, USA.,Zymo Research Corp., 17062 Murphy Ave, Irvine, CA 92614, USA
| | | | - Anna E Romano
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Alyssa M Carter
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Mi Kyung Kim
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Matt Thomson
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Colten Tognazzini
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Matthew Feaster
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Ying-Ying Goh
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Yap Ching Chew
- Pangea Laboratory LLC, 14762 Bentley Cir, Tustin, CA 92780, USA.,Zymo Research Corp., 17062 Murphy Ave, Irvine, CA 92614, USA
| | - Rustem F Ismagilov
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
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Carter AM, Viloria Winnett A, Romano AE, Akana R, Shelby N, Ismagilov RF. Laboratory Evaluation Links Some False-Positive COVID-19 Antigen Test Results Observed in a Field Study to a Specific Lot of Test Strips. Open Forum Infect Dis 2023; 10:ofac701. [PMID: 36726541 PMCID: PMC9887260 DOI: 10.1093/ofid/ofac701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
During a household-transmission field study using COVID-19 antigen rapid diagnostic tests (Ag-RDT), a common test strip lot was identified among 3 participants with false-positive results. In blinded laboratory evaluation, this lot exhibited a significantly higher false-positive rate than other lots. Because a positive Ag-RDT result often prompts action, reducing lot-specific false positives can maintain confidence and actionability of true-positive Ag-RDT results.
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Affiliation(s)
- Alyssa M Carter
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | | | - Anna E Romano
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Reid Akana
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Natasha Shelby
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Rustem F Ismagilov
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
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Viloria Winnett A, Porter MK, Romano AE, Savela ES, Akana R, Shelby N, Reyes JA, Schlenker NW, Cooper MM, Carter AM, Ji J, Barlow JT, Tognazzini C, Feaster M, Goh YY, Ismagilov RF. Morning SARS-CoV-2 Testing Yields Better Detection of Infection Due to Higher Viral Loads in Saliva and Nasal Swabs upon Waking. Microbiol Spectr 2022; 10:e0387322. [PMID: 36287073 PMCID: PMC9769854 DOI: 10.1128/spectrum.03873-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 01/10/2023] Open
Abstract
Optimizing specimen collection methods to achieve the most reliable SARS-CoV-2 detection for a given diagnostic sensitivity would improve testing and minimize COVID-19 outbreaks. From September 2020 to April 2021, we performed a household-transmission study in which participants self-collected specimens every morning and evening throughout acute SARS-CoV-2 infection. Seventy mildly symptomatic participants collected saliva, and of those, 29 also collected nasal swab specimens. Viral load was quantified in 1,194 saliva and 661 nasal swab specimens using a high-analytical-sensitivity reverse transcription-quantitative PCR (RT-qPCR) assay. Viral loads in both saliva and nasal swab specimens were significantly higher in morning-collected specimens than in evening-collected specimens after symptom onset. This aspect of the biology of SARS-CoV-2 infection has implications for diagnostic testing. We infer that morning collection would have resulted in significantly improved detection and that this advantage would be most pronounced for tests with low to moderate analytical sensitivity. Collecting specimens for COVID-19 testing in the morning offers a simple and low-cost improvement to clinical diagnostic sensitivity of low- to moderate-analytical-sensitivity tests. IMPORTANCE Our findings suggest that collecting saliva and nasal swab specimens in the morning immediately after waking yields higher SARS-CoV-2 viral loads than collection later in the day. The higher viral loads from morning specimen collection are predicted to significantly improve detection of SARS-CoV-2 in symptomatic individuals, particularly when using moderate- to low-analytical-sensitivity COVID-19 diagnostic tests, such as rapid antigen tests.
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Affiliation(s)
| | | | - Anna E. Romano
- California Institute of Technology, Pasadena, California, USA
| | - Emily S. Savela
- California Institute of Technology, Pasadena, California, USA
| | - Reid Akana
- California Institute of Technology, Pasadena, California, USA
| | - Natasha Shelby
- California Institute of Technology, Pasadena, California, USA
| | | | | | | | | | - Jenny Ji
- California Institute of Technology, Pasadena, California, USA
| | - Jacob T. Barlow
- California Institute of Technology, Pasadena, California, USA
| | - Colten Tognazzini
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Matthew Feaster
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Ying-Ying Goh
- City of Pasadena Public Health Department, Pasadena, California, USA
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Savela ES, Viloria Winnett A, Romano AE, Porter MK, Shelby N, Akana R, Ji J, Cooper MM, Schlenker NW, Reyes JA, Carter AM, Barlow JT, Tognazzini C, Feaster M, Goh YY, Ismagilov RF. Quantitative SARS-CoV-2 Viral-Load Curves in Paired Saliva Samples and Nasal Swabs Inform Appropriate Respiratory Sampling Site and Analytical Test Sensitivity Required for Earliest Viral Detection. J Clin Microbiol 2022; 60:e0178521. [PMID: 34911366 PMCID: PMC8849374 DOI: 10.1128/jcm.01785-21] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022] Open
Abstract
Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and presymptomatic transmission, curb the spread of variants, and maximize treatment efficacy. Low-analytical-sensitivity nasal-swab testing is commonly used for surveillance and symptomatic testing, but the ability of these tests to detect the earliest stages of infection has not been established. In this study, conducted between September 2020 and June 2021 in the greater Los Angeles County, California, area, initially SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity reverse-transcription quantitative PCR (RT-qPCR) and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, testing saliva with a high-analytical-sensitivity assay detected infection up to 4.5 days before viral loads in nasal swabs reached concentrations detectable by low-analytical-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva but were undetectable or at lower loads during the first few days of infection. High-analytical-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to designing optimal testing strategies with emerging variants in the current pandemic and to respond to future viral pandemics.
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Affiliation(s)
- Emily S. Savela
- California Institute of Technology, Pasadena, California, USA
| | | | - Anna E. Romano
- California Institute of Technology, Pasadena, California, USA
| | | | - Natasha Shelby
- California Institute of Technology, Pasadena, California, USA
| | - Reid Akana
- California Institute of Technology, Pasadena, California, USA
| | - Jenny Ji
- California Institute of Technology, Pasadena, California, USA
| | | | | | | | | | - Jacob T. Barlow
- California Institute of Technology, Pasadena, California, USA
| | - Colten Tognazzini
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Matthew Feaster
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Ying-Ying Goh
- City of Pasadena Public Health Department, Pasadena, California, USA
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Savela ES, Winnett A, Romano AE, Porter MK, Shelby N, Akana R, Ji J, Cooper MM, Schlenker NW, Reyes JA, Carter AM, Barlow JT, Tognazzini C, Feaster M, Goh YY, Ismagilov RF. Quantitative SARS-CoV-2 viral-load curves in paired saliva and nasal swabs inform appropriate respiratory sampling site and analytical test sensitivity required for earliest viral detection. medRxiv 2021:2021.04.02.21254771. [PMID: 33851180 PMCID: PMC8043477 DOI: 10.1101/2021.04.02.21254771] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and pre-symptomatic transmission, curb the spread of variants by travelers, and maximize treatment efficacy. Low-sensitivity nasal-swab testing (antigen and some nucleic-acid-amplification tests) is commonly used for surveillance and symptomatic testing, but the ability of low-sensitivity nasal-swab tests to detect the earliest stages of infection has not been established. In this case-ascertained study, initially-SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity RT-qPCR and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, high-sensitivity saliva testing detected infection up to 4.5 days before viral loads in nasal swabs reached the limit of detection of low-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva, but were undetectable or at lower loads during the first few days of infection. High-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to design optimal testing strategies in the current pandemic and will be required for responding to future viral pandemics. As new variants and viruses emerge, up-to-date data on viral kinetics are necessary to adjust testing strategies for reliable early detection of infections.
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Affiliation(s)
- Emily S. Savela
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Alexander Winnett
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Anna E. Romano
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Michael K. Porter
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Natasha Shelby
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Reid Akana
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jenny Ji
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Matthew M. Cooper
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Noah W. Schlenker
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jessica A. Reyes
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Alyssa M. Carter
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jacob T. Barlow
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Colten Tognazzini
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Matthew Feaster
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Ying-Ying Goh
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Rustem F. Ismagilov
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
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Mansfield MW, Stickland MH, Carter AM, Grant PJ. Polymorphisms of the Plasminogen Activator Inhibitor- 1 Gene in Type 1 and Type 2 Diabetes, and in Patients with Diabetic Retinopathy. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1642514] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryTo identify whether genotype contributes to the difference in PAI-1 levels in type 1 and type 2 diabetic subjects and whether genotype relates to the development of retinopathy, a Hind III restriction fragment length polymorphism and two dinucleotide repeat polymorphisms were studied. In 519 Caucasian diabetic subjects (192 type 1, 327 type 2) and 123 Caucasian control subjects there were no differences in the frequency of the Hind III restriction alleles (type 1 vs type 2 vs control: allele 1 0.397 vs 0.420 vs 0.448; allele 2 0.603 vs 0.580 vs 0.552) nor in the allelic frequency at either dinucleotide repeat sequence. In 86 subjects with no retinopathy at 15 years or more from diagnosis of diabetes and 190 subjects with diabetic retinopathy there was no difference in the frequency of Hind III restriction alleles (retinopathy present vs retinopathy absent: allele 1 0.400 vs 0.467; allele 2 0.600 vs 0.533) nor in the allelic frequencies at either dinucleotide repeat sequence. The results indicate that there is no or minimal influence of the PAI-1 gene on either PAI-1 levels or the development of diabetic retinopathy in patients with diabetes mellitus.
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Affiliation(s)
- M W Mansfield
- The Diabetes and Thrombosis Research Group, The Divison of Medicine, The School of Medicine, University of Leeds, Leeds General Infirmary, Leeds, UK
| | - M H Stickland
- The Diabetes and Thrombosis Research Group, The Divison of Medicine, The School of Medicine, University of Leeds, Leeds General Infirmary, Leeds, UK
| | - A M Carter
- The Diabetes and Thrombosis Research Group, The Divison of Medicine, The School of Medicine, University of Leeds, Leeds General Infirmary, Leeds, UK
| | - P J Grant
- The Diabetes and Thrombosis Research Group, The Divison of Medicine, The School of Medicine, University of Leeds, Leeds General Infirmary, Leeds, UK
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Affiliation(s)
- A M Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Abstract
BACKGROUND Dietrich Starck (1908-2001) was a German embryologist who wrote extensive reviews on comparative placentation. FINDINGS Starck's embryology textbook and his comprehensive review of comparative embryology and placentation give excellent insights into the foundational literature and are extensively referenced. The many original illustrations include placentas from species that are not well described elsewhere. CONCLUSIONS These resources are especially valuable as a portal to the early literature on comparative placentation.
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Affiliation(s)
- A M Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
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Carter AM, Mess AM. Placentation in the colugos Cynocephalus volans and Galeopterus variegatus (Dermoptera) and the transition from labyrinthine to villous placentation in primates. Placenta 2017. [PMID: 28623972 DOI: 10.1016/j.placenta.2017.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Phylogenetics and genomics place colugos as the sister group to primates. Therefore their placentation is of interest in an evolutionary perspective. Previous accounts are fragmentary, not readily accessible and sometimes contradictory. METHODS We have examined archival material covering the early development of fetal membranes and placenta, the fate of the yolk sac and definitive placentation. RESULTS Initially the trophoblast extended over a rather broad but shallow area, enclosing maternal blood spaces. After expansion of the exocoelom it became covered by somatic mesoderm. The mature chorioallantoic placenta was haemochorial and characterized by a labyrinth with markedly dilated maternal blood spaces. Blood vessels appeared in the splanchnopleure early in development and later extended to the yolk sac, but we found no evidence of a choriovitelline placenta at any stage of gestation. There was, however, an extensive paraplacenta. CONCLUSIONS A choriovitelline placenta is not formed early in gestation nor is it present at term. Early in development invasive trophoblast spreads laterally to form a trophoblastic plate. We found evidence to support the idea that the colugo placenta is intermediate between the labyrinthine placenta of rodents and the trabecular type of Neotropical primates.
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Affiliation(s)
- A M Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
| | - A M Mess
- Department of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Av. Prof. Orlando Marques de Paiva 87, Butanta, 05508-270, Sao Paulo, S. P., Brazil
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Vercruysse L, Carter AM, Pijnenborg R. The role of the placenta in the initiation of spiral artery remodelling in an early pregnant chimpanzee uterus. Placenta 2017; 53:83-91. [PMID: 28487026 DOI: 10.1016/j.placenta.2017.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/02/2017] [Accepted: 04/03/2017] [Indexed: 01/08/2023]
Abstract
INTRODUCTION In this study we evaluated the full extent of placental bed changes (centre to periphery) in a pregnant chimpanzee uterus, kept at the Museum for Central Africa in Tervuren, Belgium. According to placental size the specimen was equivalent to an 8 weeks pregnant human uterus. METHODS Histological sections from central to peripheral tissue blocks of the placental bed were stained to reveal the presence of trophoblast, endothelium, vascular smooth muscle and elastic laminae. As an indicator for early arterial remodelling, we evaluated endothelial nuclear rounding and subendothelial vascular changes within the maternal vasculature in decidua and adjacent inner myometrium. RESULTS While interstitially invading trophoblasts were present, endovascular trophoblast invasion seemed about to start into one spiral artery outlet at the centre of the placental bed, confirming our previous impression of a later onset of endovascular trophoblast invasion as compared to the human. An early sign of spiral artery remodelling was rounding of the endothelial nuclei. This phenomenon was not related to the local presence of interstitial trophoblast. DISCUSSION Endothelial nuclear rounding turned out to be a feature of the placental bed as a whole, being significantly less prominent in the adjacent non-placental bed part of the uterus, indicating an effect of the presence of the placenta. The different time-course of early spiral artery remodelling in the chimpanzee as compared to the human may have had a significant impact upon our evolution.
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Affiliation(s)
- L Vercruysse
- Department of Woman & Child, University Hospital Leuven, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - A M Carter
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - R Pijnenborg
- Department of Woman & Child, University Hospital Leuven, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
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Abstract
BACKGROUND Transmission electron microscopy (TEM) was first applied to study placental ultrastructure in the 1950's. We review those early studies and mention the scientists that employed or encouraged the use of TEM. FINDINGS Among the pioneers Edward W. Dempsey was a key figure who attracted many other scientists to Washington University in St. Louis. Work on human placental ultrastructure was initiated at Cambridge and Kyoto whilst domestic animals were initially studied by Björkman in Stockholm and electron micrographs of bat placenta were published by Wimsatt of Cornell University. CONCLUSIONS Prior to the introduction of better fixation techniques, TEM images were of modest technical quality. Nevertheless they gave important insights into placental ultrastructure, particularly the nature of the maternal-fetal interface.
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Affiliation(s)
- A M Carter
- Cardiovascular and Renal Physiology, Institute of Molecular Medicine, University of Southern Denmark, J. B. Winsløws Vej 21, DK-5000 Odense, Denmark.
| | - A C Enders
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, CA 95616, USA
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Carter AM. Editorial. Trophoblast Research. Placenta 2013; 35 Suppl:S1. [PMID: 24231446 DOI: 10.1016/j.placenta.2013.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 11/16/2022]
Affiliation(s)
- A M Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, J. B. Winsloews Vej 21, DK-5000 Odense, Denmark.
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Carter AM, Enders AC, Jones CJP, Keovichit PK, Hugot JP. A new form of rodent placentation in the relict species, Laonastes aenigmamus (Rodentia: Diatomyidae). Placenta 2013; 34:548-58. [PMID: 23643068 DOI: 10.1016/j.placenta.2013.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The Laotian rock rat is a relict species in a sister group relationship to hystricognath rodents (Hystricognathi). We asked whether there were similarities in placentation that might reflect this relationship or differences that might cast light on the evolution of Hystricognathi. METHODS We examined the reproductive tract of nonpregnant (n = 5), early (n = 3) and mid to late gestation (n = 2) females. Selected characters were mapped to a phylogenetic tree to examine their evolution in rodents. RESULTS The chorionic placenta was discoid and labyrinthine with a spongy zone but without internal lobes. The interhemal region was hemodichorial with syncytiotrophoblast lining maternal blood spaces and an inner layer of vacuolated cytotrophoblast. There was no subplacenta. The yolk sac was well developed with a villous portion that faced the placental disk but no fibrovascular ring. There was a single fetus that very likely would be precocial at birth. DISCUSSION A lobulated labyrinth and the presence of a subplacenta and a fibrovascular ring emerged as synapomorphies for Hystricognathi. Laonastes, Ctenodactylus and stem Hystricognathi all had precocial young, whereas altriciality was the plesiomorphic condition for rodents. A hemomonochorial interhemal region was plesiomorphic for rodents and Hystricognathi, and the hemodichorial condition found in Laonastes, and possibly in Ctenodactylus, was unlike that of any rodent studied to date. CONCLUSION Similar to Hystricognathi, Laonastes bears precocial young, but this species lacks placental adaptations such as the subplacenta, suggesting they were evolved subsequent to a change in reproductive strategy in the common ancestor of Laonastes and Hystricognathi.
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Affiliation(s)
- A M Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark.
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Carter AM. Trophoblast Research is a record of the annual meetings of the International Federation of Placenta Associations (IFPA). Placenta 2012; 34 Suppl:S1. [PMID: 23237532 DOI: 10.1016/j.placenta.2012.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 11/23/2012] [Indexed: 11/26/2022]
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Ackerman WE, Carter AM, De Mestre AM, Golos TG, Jeschke U, Kusakabe K, Laurent LC, Parast MM, Roberts RM, Robinson JM, Rutherford J, Soma H, Takizawa T, Ui-Tei K, Lash GE. IFPA Meeting 2012 Workshop Report I: comparative placentation and animal models, advanced techniques in placental histopathology, human pluripotent stem cells as a model for trophoblast differentiation. Placenta 2012. [PMID: 23206905 DOI: 10.1016/j.placenta.2012.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of models and technical issues involved in placenta research: 1) comparative placentation and animal models; 2) advanced techniques in placental histopathology; 3) human pluripotent stem cells as a model for trophoblast differentiation.
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Affiliation(s)
- W E Ackerman
- Laboratory of Perinatal Research, Department of Obstetrics and Gynaecology, The Ohio State University, Columbus, OH, USA
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Hess K, Alzahrani SH, Mathai M, Schroeder V, Carter AM, Howell G, Koko T, Strachan MWJ, Price JF, Smith KA, Grant PJ, Ajjan RA. A novel mechanism for hypofibrinolysis in diabetes: the role of complement C3. Diabetologia 2012; 55:1103-13. [PMID: 21918806 DOI: 10.1007/s00125-011-2301-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 08/12/2011] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Impaired fibrin clot lysis is a key abnormality in diabetes and complement C3 is one protein identified in blood clots. This work investigates the mechanistic pathways linking C3 and hypofibrinolysis in diabetes using ex vivo/in vitro studies. METHODS Fibrinolysis and C3 plasma levels were determined in type 1 diabetic patients and healthy controls, and the effects of glycaemia investigated. C3 incorporation into fibrin clots and modulation of fibrinolysis were analysed by ELISA, immunoblotting, turbidimetric assays and electron and confocal microscopy. RESULTS Clot lysis time was longer in diabetic children than in controls (599 ± 18 and 516 ± 12 s respectively; p < 0.01), C3 levels were higher in diabetic children (0.55 ± 0.02 and 0.43 ± 0.02 g/l respectively; p < 0.01) and both were affected by improving glycaemia. An interaction between C3 and fibrin was confirmed by the presence of lower protein levels in sera compared with corresponding plasma and C3 detection in plasma clots by immunoblot. In a purified system, C3 was associated with thinner fibrin fibres and more prolongation of lysis time of clots made from fibrinogen from diabetic participants compared with controls (244 ± 64 and 92 ± 23 s respectively; p < 0.05). Confocal microscopy showed higher C3 incorporation into diabetic clots compared with controls, and fully formed clot lysis was prolonged by 764 ± 76 and 428 ± 105 s respectively (p < 0.05). Differences in lysis, comparing diabetes and controls, were not related to altered plasmin generation or C3-fibrinogen binding assessed by plasmon resonance. CONCLUSIONS/INTERPRETATION C3 incorporation into clots from diabetic fibrinogen is enhanced and adversely affects fibrinolysis. This may be one novel mechanism for compromised clot lysis in diabetes, potentially offering a new therapeutic target.
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Affiliation(s)
- K Hess
- University of Leeds, Leeds, UK
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James JL, Carter AM, Chamley LW. Human placentation from nidation to 5 weeks of gestation. Part II: Tools to model the crucial first days. Placenta 2012; 33:335-42. [PMID: 22365889 DOI: 10.1016/j.placenta.2012.01.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 01/19/2012] [Accepted: 01/30/2012] [Indexed: 12/21/2022]
Abstract
Human pregnancy is unusual with respect to monthly spontaneous decidualisation as well as the degree of placental invasion and interaction with the decidualised endometrial stroma. This review covers in vivo animal models and in vitro cell culture models that have been used to study the earliest stages of human implantation and placentation from nidation to 5 weeks of gestation. The field has expanded rapidly in recent years due to the generation of human embryonic stem cell lines and the ability of some scientists to culture human blastocysts. These models have enabled researchers to begin to elucidate the interactions involved in human blastocyst apposition, adhesion and implantation. However, we still understand very little about the differentiation processes involved in the formation of the placenta. Continued improvements to current models, including the potential isolation of a human trophoblast stem cell, will significantly enhance our ability to define the molecular and structural events occurring during human implantation and early placental development.
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Affiliation(s)
- J L James
- Department of Obstetrics and Gynecology, University of Auckland, 85 Park Rd, Grafton, Auckland, New Zealand.
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Ackerman WE, Bulmer JN, Carter AM, Chaillet JR, Chamley L, Chen CP, Chuong EB, Coleman SJ, Collet GP, Croy BA, de Mestre AM, Dickinson H, Ducray J, Enders AC, Fogarty NME, Gauster M, Golos T, Haider S, Heazell AE, Holland OJ, Huppertz B, Husebekk A, John RM, Johnsen GM, Jones CJP, Kalionis B, König J, Lorenzon AR, Moffett A, Moreira de Mello JC, Nuzzo AM, Parham P, Parolini O, Petroff MG, Pidoux G, Ramírez-Pinilla MP, Robinson WP, Rolfo A, Sadovsky Y, Soma H, Southcombe JH, Tilburgs T, Lash GE. IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells. Placenta 2011; 33 Suppl:S15-22. [PMID: 22154501 DOI: 10.1016/j.placenta.2011.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 11/22/2011] [Accepted: 11/24/2011] [Indexed: 10/14/2022]
Abstract
Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.
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Affiliation(s)
- W E Ackerman
- Laboratory of Perinatal Research, Department of Obstetrics and Gynecology, The Ohio State University, Columbus, OH, USA
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Pijnenborg R, Vercruysse L, Carter AM. Deep trophoblast invasion and spiral artery remodelling in the placental bed of the lowland gorilla. Placenta 2011; 32:586-91. [PMID: 21705078 DOI: 10.1016/j.placenta.2011.05.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/13/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
Abstract
In contrast to baboon or rhesus macaque, trophoblast invasion in the human placental bed occurs by the interstitial as well as the endovascular route and reaches as deep as the inner myometrium. We here describe two rare specimens of gorilla placenta. In the light of recent findings in the chimpanzee, we postulated the occurrence of deep invasion in gorilla pregnancy. Tissues were processed for histology (PAS, orcein), lectin staining (Ulex europaeus agglutinin 1) and immunohistochemistry (cytokeratin 7/17, α-actin). A specimen of young but undetermined gestational age included deep placental bed tissue, showing interstitial and spiral artery invasion of the inner myometrium as well as the decidua. The cell density and depth of trophoblast invasion was equivalent to a human placental bed of 10-14 weeks. Intraluminal trophoblasts were not seen in any of the invaded vessels, allowing no definite conclusions about the origin of the intramural trophoblast and the time-course of spiral artery invasion. A different late second trimester placenta specimen showed scattered extravillous trophoblast in the basal plate and underlying decidua, as well as a remodelled spiral artery containing intramural trophoblast. Absence of inner myometrial tissue precluded assessment of invasion depth in this later specimen. Despite the limited material we can conclude that key aspects of trophoblast invasion are shared by the three hominid species: gorilla, chimpanzee and human.
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Affiliation(s)
- R Pijnenborg
- Department of Woman & Child, University Hospital Leuven, Katholieke Universiteit Leuven, Leuven, Belgium.
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Pijnenborg R, Vercruysse L, Carter AM. Deep trophoblast invasion and spiral artery remodelling in the placental bed of the chimpanzee. Placenta 2011; 32:400-8. [PMID: 21459441 DOI: 10.1016/j.placenta.2011.02.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 02/25/2011] [Accepted: 02/25/2011] [Indexed: 10/18/2022]
Abstract
Deep trophoblast invasion is usually considered to be a unique feature of human placentation as compared to other primates. Because of the occasional occurrence of preeclampsia in great apes, which in the human is associated with impaired deep invasion, this uniqueness may be questioned. The availability of two well-documented pregnant chimpanzee uteri in the Hubrecht Collection (Museum für Naturkunde, Berlin) allowed us to evaluate the extent of trophoblast invasion in this species. By adjusting currently used protocols, we obtained successful immunohistochemical staining for cytokeratin and α-actin, as well as Ulex europaeus agglutinin 1 (UEA1) lectin staining, in this archival material. In both specimens interstitial trophoblast invasion had occurred in both decidua and myometrium. Because of a lack of published data on fetal growth for this species, fetal sizes (7cm and 13cm) could not be strictly related to gestational ages and thus be compared with the time-course of human trophoblast invasion. However, since the earlier specimen did not show any endovascular trophoblast invasion in spiral arteries - in contrast to pregnant human uteri with equivalent fetal sizes - endovascular migration seems to begin at a different gestational age in the chimpanzee. In the later specimen endovascular trophoblast was associated with spiral artery remodelling in the inner myometrium, and this invasion was extended to include a radial artery, which at that stage still showed relatively intact vascular smooth muscle and elastic lamina. We conclude that invasion depth and spiral artery remodelling are basically similar in chimpanzees and humans, although the seemingly different time of onset may have implications for uteroplacental oxygen supply and fetal development.
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Affiliation(s)
- R Pijnenborg
- Department of Woman & Child, University Hospital Leuven, Katholieke Universiteit Leuven, Belgium
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Carter AM. Placenta. Trophoblast Research. Editorial. Placenta 2011; 32 Suppl 2:S77. [PMID: 21353097 DOI: 10.1016/j.placenta.2010.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 11/15/2010] [Accepted: 11/17/2010] [Indexed: 10/18/2022]
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Schroeder V, Carter AM, Dunne J, Mansfield MW, Grant PJ. Proinflammatory and hypofibrinolytic phenotype in healthy first-degree relatives of patients with Type 2 diabetes. J Thromb Haemost 2010; 8:2080-2. [PMID: 20586918 DOI: 10.1111/j.1538-7836.2010.03966.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
A recent phylogenetic analysis achieved good resolution between the 5 suborders of rodent. As a novel finding it suggested a basal split that gave rise to a monophyletic group comprising Hystricomorpha and Sciuromorpha. We asked whether the new tree could cast light on the evolution of the interhaemal barrier in rodents where at least seven variants have been described. To supplement existing data we first examined the placenta of the common gundi, Ctenodactylus gundi. It was shown to be haemochorial with a single layer of syncytiotrophoblast in the interhaemal membrane but with nests of cytotrophoblast elsewhere. Next we used character mapping on the recent tree to determine the pattern of evolution of the placenta with respect to principal type (e.g. haemochorial) and the trophoblast found within the interhaemal barrier. This indicated that the common ancestor of living rodents had a haemochorial placenta and that there were two independent transformations to the endotheliochorial type. Moreover, the interhaemal barrier was found to have had a single layer of syncytial trophoblast in the common ancestor of rodents, a condition that was retained in the clade comprising Hystricomorpha and Sciuromorpha. In contrast the second clade shows multiple character transformations.
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Affiliation(s)
- A M Mess
- Department of Research, Museum of Natural History, Leibniz-Community, Berlin, Germany
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Jones CJP, Carter AM, Bennett NC, Blankenship TN, Enders AC. Placentation in the Hottentot golden mole, Amblysomus hottentotus (Afrosoricida: Chrysochloridae). Placenta 2009; 30:571-8. [PMID: 19501397 DOI: 10.1016/j.placenta.2009.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 04/29/2009] [Accepted: 04/30/2009] [Indexed: 11/17/2022]
Abstract
The placentation of the Hottentot golden mole (Amblysomus hottentotus) has been examined using light and electron microscopy and lectin histochemistry of nine specimens at both mid and late gestation. The placentae were lobulated towards the allantoic surface and the lobules contained roughly parallel arrays of labyrinthine structures converging on a central spongy zone. At mid gestation, the arrays were composed of an inner cellular and outer syncytial trophoblast layer, the inner layer enclosing scant connective tissue and fetal capillaries. Maternal blood spaces coursed through the outer trophoblast and were lined by trophoblastic microvilli; the blood spaces were narrow in mid gestation but enlarged near term, while the inner trophoblast layer became thinner and seemed to be syncytial. These features were confirmed by transmission electron microscopy. The microvillous surfaces and dispersed cytoplasmic particles were heavily glycosylated, as shown by lectin histochemistry, and exhibited changes with maturation, particularly a loss in N-acetyl glucosamine oligomers bound by Phytolacca americana lectin on the microvilli lining the maternal blood spaces and outer trophoblast particles. A substantial yolk sac was present both in mid and late gestation stages. It was clearly unattached to the uterus in the later stages. These morphological features are discussed in relation to the phylogenetic position of Amblysomus with respect to other members of Afrosoricida and Afrotheria.
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Affiliation(s)
- C J P Jones
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester M13 OJH, UK
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Carter AM, Nilsén R, Bengtsson LP. The effect of vasopressin on myometrial blood flow in the pregnant rabbit. Acta Pharmacol Toxicol (Copenh) 2009; 26:29-34. [PMID: 5694262 DOI: 10.1111/j.1600-0773.1967.tb00423.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Scott EM, Carter AM, Grant PJ. Diabetes and cardiovascular disease: related disorders created by disturbances in the endogenous clock. J Indian Med Assoc 2008; 106:736-740. [PMID: 19368099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The factors underpinning the development of type 2 diabetes mirror closely the presentation of atherothrombotic risk factors that enhance risk of macrovascular disease. It has been postulated that this relationship is so tight as to indicate that diabetes and cardiovascular disease are the same condition with common genetic and environmental antecedents ('the common soil hypothesis'). The huge Increase in prevalence of type 2 diabetes in the Asia-Pacific region in recent years has raised serious concerns regarding the cardiovascular consequences for these populations. For example, in the UK, subjects of S. Asian origin have a higher prevalence of type 2 diabetes with a relative risk of macrovascular disease of -1.5 compared to the Indigenous population. Current opinion favours the view that the development of obesity is associated with an insulin resistant phenotype that promotes vascular risk. Our endogenous clock is regulated centrally in the hypothalamus by light exposure and in peripheral tissues to place our metabolic needs in time with day length and the seasons. Evidence from animal and cellular studies with early data from human studies indicates that disruption of the endogenous clock as can occur with obesity, is associated with a metabolic syndrome phenotype. The adaption of western lifestyles by S Asian subjects may promote disruption of circadian rhythms with associated increases in both diabetes and cardiovascular disease.
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Affiliation(s)
- Eleanor M Scott
- Division of Cardiovascular and Diabetes Research, University of Leeds, Leeds, UK
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Abstract
BACKGROUND Alanine aminotransferase (ALT) predicts the development of Type 2 diabetes mellitus and cardiovascular disease in Caucasian subjects. OBJECTIVES This study aimed to determine the incidence of an elevated ALT and its relationship to metabolic and atherothrombotic risk factors in a healthy British South Asian population. PATIENTS/METHODS One hundred and forty-three participants from the West Yorkshire community were recruited randomly from general practice registers and were grouped according to whether their ALT was above or within the normal range (cut-off 35 IU L(-1)) and examined for differences in metabolic and atherothrombotic risk factors. All participants were originally from South Asia, with their grandparents being born in India, Pakistan, or Bangladesh. RESULTS The incidence of a raised ALT was 24%. Those with a raised ALT had a more adverse metabolic profile, with significantly higher body mass index, waist/hip ratio, fasting insulin, glucose, homeostasis model assessment homeostasis model assessment insulin resistance (HOMA-IR), and triglycerides, and lower high-density lipoprotein (HDL) cholesterol. Fifty per cent had the metabolic syndrome [International Diabetes Federation (IDF) criteria]. They also had a more adverse atherothrombotic profile, with higher tissue-type plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) antigen. In accordance, the group as a whole showed a positive correlation of ALT (age-adjusted) with waist/hip ratio, insulin, glucose, triglycerides, PAI-1 antigen, factor XIII B subunit, and FXII, and a negative correlation with HDL cholesterol. CONCLUSION Raised ALT is common in apparently healthy British South Asians, and is significantly associated with an adverse metabolic and atherothrombotic risk profile.
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Affiliation(s)
- K Kain
- Division of Cardiovascular and Diabetes Research, The LIGHT Laboratories, Clarendon Way, University of Leeds, Leeds, UK.
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Abstract
A rich source of material for comparative studies of the placenta is the collections made by pioneers in the field such as H.W. Mossman, A.A.W. Hubrecht and J.P. Hill. This overview gives a brief description of collections known to be available and information on how each can be accessed. Included are some of the major series of human and animal embryos, such as the Boyd and Carnegie collections, as these also house placental material.
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Affiliation(s)
- A M Carter
- Physiology and Pharmacology, University of Southern Denmark, J. B. Winsloewvej 21, DK-5000 Odense, Denmark.
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Miglino MA, Pereira FTV, Visintin JA, Garcia JM, Meirelles FV, Rumpf R, Ambrósio CE, Papa PC, Santos TC, Carvalho AF, Leiser R, Carter AM. Placentation in cloned cattle: Structure and microvascular architecture. Theriogenology 2007; 68:604-17. [PMID: 17568663 DOI: 10.1016/j.theriogenology.2007.04.060] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
To elucidate the morphological differences between placentas from normal and cloned cattle pregnancies reaching term, the umbilical cord, placentomes and interplacentomal region of the fetal membranes were examined macroscopically as well as by light and scanning electron microscopy. In pregnancies established by somatic nucleus transfer (NT), the umbilical cord and fetal membranes were edematous. Placentomal fusion was common, resulting in increased size and a decreased number of placentomes. Extensive areas of the chorioallantoic membrane were devoid of placentomes. An increased number of functional or accessory microcotyledons (<1 cm) were present at the maternally oriented surface of fetal membranes. Extensive areas of extravasated maternal blood were present within the placentomes and in the interplacentomal region. The crypts on the caruncular surface were dilated and accommodated complexes of more than one primary villus, as opposed to a single villus in non-cloned placentae. Scanning electron microscopy of blood vessel casts revealed that there was also more than one stem artery per villous tree and that the ramification of the vessels failed to form dense complexes of capillary loops and sinusoidal dilations as in normal pregnancies. At the materno-fetal interface, however, the trophoblast and uterine epithelium had normal histology. In conclusion, the NT placentas had a range of pathomorphological changes; this was likely associated with the poor clinical outcome of NT pregnancies.
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Affiliation(s)
- M A Miglino
- Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, São Paulo, SP, Brazil.
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Enders AC, Blankenship TN, Goodman SM, Soarimalala V, Carter AM. Placental Diversity in Malagasy Tenrecs: Placentation in Shrew Tenrecs (Microgale spp.), The Mole-Like Rice Tenrec (Oryzorictes hova) and The Web-Footed Tenrec (Limnogale mergulus). Placenta 2007; 28:748-59. [PMID: 17113148 DOI: 10.1016/j.placenta.2006.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 09/28/2006] [Accepted: 10/03/2006] [Indexed: 11/17/2022]
Abstract
Placentation in tenrecs of the subfamily Oryzorictinae, family Tenrecidae, has not been described previously. The structure of the placenta of this group and especially of the genus Microgale was investigated to determine its similarity or dissimilarity to previously described placentas of the tenrec subfamilies Potamogalinae and Tenrecinae. Fifteen specimens of the genus Microgale ranging from an early yolk sac stage to near term were available for study. Placentation in Microgale was found to be different from other tenrecids in that there is an early simple lateral rather than central haemophagous region. In addition, a more villous portion of the placental disk forms before the formation of a more compact labyrinth. Although the definitive placenta is cellular haemomonochorial, it lacks the spongy zone found in the Tenrecinae. Neither does it resemble the endotheliochorial condition found in the Potamogalinae. Of the two genera of the subfamily Oryzorictinae represented by single specimens, the placenta of Limnogale resembled that of the Microgale but Oryzorictes had several differences including a lobulated placental disk. It is concluded that there is more variation in placentation both within the subfamily Oryzorictinae and within the family Tenrecidae than would ordinarily be expected.
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Affiliation(s)
- A C Enders
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA 95616, USA
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Carter AM, Croy BA, Dantzer V, Enders AC, Hayakawa S, Mess A, Soma H. Comparative Aspects of Placental Evolution: A Workshop Report. Placenta 2007; 28 Suppl A:S129-32. [PMID: 17350679 DOI: 10.1016/j.placenta.2007.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 01/24/2007] [Indexed: 11/28/2022]
Affiliation(s)
- A M Carter
- Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark.
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Abstract
We review recent advances in our understanding of placental evolution with particular focus on the interhaemal barrier. It seems likely that the non-invasive, epitheliochorial placentation of living eutherians is a derived state. However, there is disagreement on whether the last common ancestor of eutherian mammals had an endotheliochorial placenta or a haemochorial one. Research has been stimulated by improved understanding of the relations between the orders of mammals provided by molecular phylogenetics. In part, the uncertainties arise from doubt about how to root the mammalian tree. Resolution of this issue will require improved taxon sampling in molecular analyses. At the same time, we need to foster research in comparative placentation on relevant taxa, particularly at the ultrastructural level. Only then can we ensure that information available about the placenta is adequate to capitalise on future advances in molecular phylogenetics. Examples are given of recent findings that could benefit cladistic analysis of placental evolution.
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Affiliation(s)
- A M Carter
- Physiology and Pharmacology, University of Southern Denmark, DK-5000 Odense, Denmark.
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Ajjan R, Carter AM, Somani R, Kain K, Grant PJ. Ethnic differences in cardiovascular risk factors in healthy Caucasian and South Asian individuals with the metabolic syndrome. J Thromb Haemost 2007; 5:754-60. [PMID: 17408409 DOI: 10.1111/j.1538-7836.2007.02434.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND The metabolic syndrome is a cluster of atherothrombotic risk factors that are commonly associated with insulin resistance. OBJECTIVES The aim of this study was to investigate ethnic differences in insulin resistance and non-traditional cardiovascular risk factors in relation to the International Diabetes Federation (IDF) definition of the metabolic syndrome. PATIENTS AND METHODS A total of 245 healthy South Asians and 245 age- and sex-matched Caucasians were studied. C-reactive protein (CRP), complement C3, plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA) were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated from fasting plasma glucose and insulin levels. RESULTS Fifty Caucasian (20%) and 95 (39%) South Asian subjects had the metabolic syndrome as defined by the IDF. In South Asian subjects, HOMA-IR, CRP, C3, PAI-1 and t-PA were significantly higher in subjects with the metabolic syndrome. In contrast, in Caucasian individuals there was no difference in HOMA-IR or C3 levels and only CRP, PAI-1 and t-PA were higher in subjects with the metabolic syndrome. In a logistic regression model, plasma levels of CRP and PAI-1 were independent predictors of the metabolic syndrome in Caucasians, whereas plasma levels of C3 and t-PA as well as HOMA-IR were independent predictors of the metabolic syndrome in South Asian subjects. CONCLUSIONS In the cohort of individuals studied, the IDF definition of the metabolic syndrome was associated with insulin resistance in the South Asian but not the Caucasian population. This work also showed ethnic differences in non-traditional cardiovascular risk factors in the presence of the metabolic syndrome.
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Affiliation(s)
- R Ajjan
- Academic Unit of Molecular Vascular Medicine, Leeds Institute of Genetics Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, Leeds, UK
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Abstract
This review examines the strengths and weaknesses of animal models of human placentation and pays particular attention to the mouse and non-human primates. Analogies can be drawn between mouse and human in placental cell types and genes controlling placental development. There are, however, substantive differences, including a different mode of implantation, a prominent yolk sac placenta, and fewer placental hormones in the mouse. Crucially, trophoblast invasion is very limited in the mouse and transformation of uterine arteries depends on maternal factors. The mouse also has a short gestation and delivers poorly developed young. Guinea pig is a good alternative rodent model and among the few species known to develop pregnancy toxaemia. The sheep is well established as a model in fetal physiology but is of limited value for placental research. The ovine placenta is epitheliochorial, there is no trophoblast invasion of uterine vessels, and the immunology of pregnancy may be quite different. We conclude that continued research on non-human primates is needed to clarify embryonic-endometrial interactions. The interstitial implantation of human is unusual, but the initial interaction between trophoblast and endometrium is similar in macaques and baboons, as is the subsequent lacunar stage. The absence of interstitial trophoblast cells in the monkey is an important difference from human placentation. However, there is a strong resemblance in the way spiral arteries are invaded and transformed in the macaque, baboon and human. Non-human primates are therefore important models for understanding the dysfunction that has been linked to pre-eclampsia and fetal growth restriction. Models that are likely to be established in the wake of comparative genomics include the marmoset, tree shrew, hedgehog tenrec and nine-banded armadillo.
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Affiliation(s)
- A M Carter
- Department of Physiology and Pharmacology, University of Southern Denmark, Winsloewparken 21, Third Floor, DK-5000 Odense, Denmark.
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Enders AC, Carter AM. Comparative Placentation: Some Interesting Modifications for Histotrophic Nutrition – A Review. Placenta 2006; 27 Suppl A:S11-6. [PMID: 16406004 DOI: 10.1016/j.placenta.2005.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 10/18/2005] [Accepted: 10/25/2005] [Indexed: 11/26/2022]
Abstract
In considering the diversity of Eutherian mammalian placental structure, it is helpful to keep in mind that both phylogenetically and ontogenetically a functional yolk sac placenta precedes development of the chorioallantoic placenta. Usually the chorioallantoic placenta progressively displaces the area of contact of the yolk sac placenta with the endometrium. It is also closely applied to the endometrium, increasing respiratory efficiency but tending to decrease histotrophic nutrition. Catarrhine primates have minimal histotrophic uptake, using haemotrophic mechanisms throughout most of gestation. Rodents, by using partial or complete inversion of the yolk sac, have extensive regions available to histotroph in later pregnancy. Most mammals, however, have developed specialized regions of the chorioallantoic placenta for ingestion of uterine secretions, cell debris and erythrocytes. These regions vary from simple saccular areolae to more complex areolae such as the chorionic vesicles of prosimian primates to specialized haemophagous areas. All such structures are consistently lined by columnar cellular trophoblast. Examples of these structures, many of which can ingest both glandular secretions and erythrocytes (i.e. they are heterophagous), can be found in species whose definitive placenta is epitheliochorial. They are common but not universal in species whose definitive placenta is endotheliochorial and are even found in a few species with definitive haemochorial placentas. Restriction of phagocytosis to regions of columnar cells provides polarized cells appropriately oriented for ingestion, breakdown and transport, and limits the type of ingestion of both beneficial and potentially toxic materials to expendable individual cells.
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Affiliation(s)
- A C Enders
- Department of Cell Biology and Human Anatomy, University of California, One Shields Avenue, Davis, CA 95616, USA.
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Carter AM, Enders AC, Jones CJP, Mess A, Pfarrer C, Pijnenborg R, Soma H. Comparative Placentation and Animal Models: Patterns of Trophoblast Invasion – A Workshop Report. Placenta 2006; 27 Suppl A:S30-3. [PMID: 16529811 DOI: 10.1016/j.placenta.2006.01.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 01/16/2006] [Indexed: 10/24/2022]
Affiliation(s)
- A M Carter
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark
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Carter AM, Nygard K, Mazzuca DM, Han VKM. The Expression of Insulin-like Growth Factor and Insulin-like Growth Factor Binding Protein mRNAs in Mouse Placenta. Placenta 2006; 27:278-90. [PMID: 16338473 DOI: 10.1016/j.placenta.2005.01.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 01/11/2005] [Accepted: 01/27/2005] [Indexed: 10/25/2022]
Abstract
Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) are paracrine regulators of tissue growth and development, and are expressed at the sites of biological action. To study the role of the IGFs and IGFBPs in mouse placental development, we determined the temporal and spatial expression patterns of the mRNAs at embryonic days 10.5 to 18.5 by in situ hybridization. IGF-II mRNA was expressed strongly in mesoderm and fetal blood vessels of early placenta and in labyrinthine trophoblast of later placenta. In the junctional zone, IGF-II mRNA was expressed first in spongiotrophoblasts, later strongly in glycogen cells and variably in giant cells. IGFBP-2 mRNA was expressed weakly in spongiotrophoblasts and glycogen cells. IGFBP-2, -5 and -6 mRNAs were detected in the stroma of the metrial gland. Myometrium expressed IGFBP-2 mRNA strongly, IGFBP-6 mRNA moderately and IGFBP-5 mRNA weakly. The endothelium of maternal blood vessels in decidua expressed IGFBP-3 and -5 mRNAs, and some deeper vessels expressed IGFBP-4 mRNA. In the yolk sac, IGF-II mRNA was expressed in endoderm and mesoderm, whereas IGFBP-1, -2 and -4 mRNAs were expressed only in endoderm, and IGFBP-4 mRNA in mesoderm. Strong expression of IGF-II mRNA in glycogen cells suggests a role in the autocrine/paracrine regulation of invasion. Similar to rat and guinea pig, but in contrast to man and primates, IGFBP mRNAs, except IGFBP-4, were not expressed in mouse decidua. However, IGFBP-3, -4 and -5 mRNAs were expressed in endothelium of maternal blood vessels, and IGFBP-2 and -6 mRNAs in myometrium, where IGFBPs may play a critical role in regulating trophoblast invasion. These findings suggest possible biological roles of the peptides at the feto-maternal interface.
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Affiliation(s)
- A M Carter
- Department of Paediatrics, University of Western Ontario, London, Ontario N6A 4V2, Canada.
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Carter AM, Blankenship TN, Enders AC, Vogel P. The Fetal Membranes of the Otter Shrews and a Synapomorphy for Afrotheria. Placenta 2006; 27:258-68. [PMID: 16338471 DOI: 10.1016/j.placenta.2005.02.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Revised: 02/25/2005] [Accepted: 02/28/2005] [Indexed: 10/25/2022]
Abstract
The otter shrews of mainland Africa are the closest relatives of the Madagascar tenrecs. We sought for similarities in placentation between the two groups and, in a wider context, with other mammals of the Afrotheria clade. Specimens of the Nimba otter shrew (Micropotamogale lamottei) were obtained from the Ivory Coast and examples of the giant otter shrew (Potamogale velox) from the Hill Collection. The Nimba otter shrew has a central haemophagous organ similar to that in tenrecs. The labyrinth of the Nimba otter shrew, however, is endotheliochorial with syncytial trophoblast enclosing the maternal vessels. On the other hand tenrecs have cellular haemomonochorial placentae and an associated spongy zone, which is not present in the Nimba otter shrew. The placenta of the giant otter shrew is also endotheliochorial. The central region of its placenta is particularly interesting, since the juxtafetal portion is clearly a haemophagous region whereas the labyrinth feeding this region is endotheliochorial. Thus there is considerable variation in placental morphology within Tenrecidae. Importantly, however, both otter shrews have a large allantoic sac divided into four intercommunicating lobes by two pairs of septal folds. A similar arrangement has been described for representatives of each of the remaining five orders within Afrotheria. This is significant because previous anatomical studies have failed to establish a single synapomorphy in support of Afrotheria.
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Affiliation(s)
- A M Carter
- Physiology and Pharmacology, University of Southern Denmark, DK-5000 Odense, Denmark.
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Oliveira MF, Carter AM, Bonatelli M, Ambrosio CE, Miglino MA. Placentation in the rock cavy, Kerodon rupestris (Wied). Placenta 2006; 27:87-97. [PMID: 16310042 DOI: 10.1016/j.placenta.2004.11.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 11/16/2004] [Accepted: 11/16/2004] [Indexed: 11/23/2022]
Abstract
Rock cavies are rodents found in the semi-arid caatinga of Brazil. We studied the structure of the rock cavy placenta by light and transmission electron microscopy. The exchange area of the labyrinth was organized in lobes separated by interlobular areas. The interhaemal barrier was syncytial haemomonochorial. The syncytiotrophoblast had recesses in the basal membrane and some invaginations of the apical membrane, but transtrophoblastic channels could not be found. The interlobular regions comprised syncytiotrophoblast, enclosing maternal venous blood channels, and cytotrophoblast. There was a prominent subplacenta composed of cytotrophoblast and syncytiotrophoblast. Microvilli projected into spaces between the cytotrophoblasts and into lacunae within the syncytiotrophoblast. The yolk sac epithelium exhibited coated pits, endocytotic vesicles and larger vacuoles, consistent with a role in protein uptake from the uterine lumen. Tight junctions between these cells provided a barrier to diffusion by the intercellular route. The reproductive biology of the rock cavy differs from other members of the family, including the guinea pig, but the architecture of the placenta remains remarkably constant.
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Affiliation(s)
- M F Oliveira
- Department of Surgery, School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil
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Abstract
AIMS To determine the influence of metformin treatment on plasma C-reactive protein (CRP) and complement factor C3. METHODS A double-blind, placebo-controlled trial of metformin in patients with poorly controlled Type 2 diabetes mellitus and body mass index > 25 kg/m2. CRP and C3 were analysed in stored plasma samples by in-house ELISAs. Patients attended two baseline visits before randomization and subsequently attended at 3, 6, 12 and 24 weeks post randomization. All patients gave informed consent according to a protocol approved by the Leeds Teaching Hospitals Research Ethics Committee. RESULTS Baseline CRP in the patients randomized to placebo [1.33 (0.79, 2.25) mg/l] and metformin [1.24 (0.89, 1.71) mg/l] were similar (P = 0.8). Baseline CRP correlated with baseline C3 (r = 0.366) and HbA1c (r = 0.327). The difference in ratios of CRP levels at each visit to baseline between placebo- (n = 16) and metformin-treated (n = 26) subjects was significantly different at the 12-week (P = 0.002) and 24-week (P = 0.03) visits. The difference in CRP ratios between the two treatment groups remained significant after accounting for glycaemic control at both visits (P = 0.001 and P = 0.003, respectively). Baseline C3 was correlated with CRP. Baseline C3 was lower in the placebo-treated group [0.97 (0.88, 1.05) mg/ml] compared with the metformin-treated group [1.09 (1.02, 1.17) mg/ml, P = 0.03]. There was no difference in the mean change in C3 at any visit from baseline between placebo- and metformin-treated groups. CONCLUSION Metformin may have a specific interaction with mechanisms involved in CRP synthesis or secretion, not directly related to improved insulin sensitivity and dampening of chronic inflammation.
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Affiliation(s)
- A M Carter
- Molecular Vascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, Leeds, UK.
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Abstract
In 1938 Mossman reported that epitheliochorial placentation occurred in an insectivore, the Eastern mole. This led to a radical change in his thinking about placental evolution, yet 40 years would pass before the appearance of a definitive description. Unpublished papers in the Mossman Collection at the University of Wisconsin Zoological Museum tell a fascinating story about this delay. The Scalopus material was studied by Mossman's graduate student, M.R.N. Prasad, who concluded that the placenta was initially endotheliochorial and that subsequent re-epithelialization of the uterus led to the definitive epitheliochorial condition. Mossman withheld publication of these findings pending electron microscopic studies. The definitive publication described the ultrastructure of the interhaemal region. Although based on a single specimen, this seemed to justify the conclusion that an epitheliochorial condition was maintained throughout gestation. These findings are discussed in relation to subsequent work on the European mole and current thinking about placental evolution.
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Affiliation(s)
- A M Carter
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense.
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Enders AC, Carter AM, Künzle H, Vogel P. Structure of the Ovaries of the Nimba Otter Shrew, Micropotamogale lamottei, and the Madagascar Hedgehog Tenrec, Echinops telfairi. Cells Tissues Organs 2005; 179:179-91. [PMID: 16046864 DOI: 10.1159/000085953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The otter shrews are members of the subfamily Potamogalinae within the family Tenrecidae. No description of the ovaries of any member of this subfamily has been published previously. The lesser hedgehog tenrec, Echinops telfairi, is a member of the subfamily Tenrecinae of the same family and, although its ovaries have not been described, other members of this subfamily have been shown to have ovaries with non-antral follicles. Examination of these two species illustrated that non-antral follicles were characteristic of the ovaries of both species, as was clefting and lobulation of the ovaries. Juvenile otter shrews range from those with only small follicles in the cortex to those with 300- to 400-microm follicles similar to those seen in non-pregnant and pregnant adults. As in other species, most of the growth of the oocyte occurred when follicles had one to two layers of granulosa cells. When larger follicles became atretic in the Nimba otter shrew, hypertrophy of the theca interna produced nodules of glandular interstitial tissue. In the tenrec, the hypertrophying theca interna cells in most large follicles appeared to undergo degeneration. Both species had some follicular fluid in the intercellular spaces between the more peripheral granulosa cells. It is suggested that this fluid could aid in separation of the cumulus from the remaining granulosa at ovulation. The protruding follicles in lobules and absence of a tunica albuginea might also facilitate ovulation of non-antral follicles. Ovaries with a thin-absent tunica albuginea and follicles with small-absent antra are widespread within both the Eulipotyphla and in the Afrosoricida, suggesting that such features may represent a primitive condition in ovarian development. Lobulated and deeply crypted ovaries are found in both groups but are not as common in the Eulipotyphla making inclusion of this feature as primitive more speculative.
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Affiliation(s)
- A C Enders
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA 95616, USA.
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Abstract
AIM We asked how adrenomedullin (AM), a vasodilator peptide, was distributed in fetal sheep organs and whether expression of AM would be upregulated in response to moderate acute fetal hypoxia in vivo. METHODS In four sheep at day 126-130 of gestation, nitrogen was added to the inspired air by tracheal infusion to reduce fetal arterial oxygen content for a period of 4 h. Control fetuses were from four ewes given a tracheal infusion of room air. Fetal and maternal blood samples were taken prior to and during hypoxia/sham hypoxia. Fetal tissue samples were frozen for RNA analysis and fixed for immunohistochemistry. RESULTS In hypoxic fetuses, arterial oxygen content was significantly reduced to 50% compared with sham fetuses with no change in arterial pH in either group. Plasma ACTH levels rose significantly at 2 and 4 h in hypoxic fetuses only. Initial plasma concentrations of AM in control and hypoxic fetuses were 457 +/- 20 and 430 +/- 35 pg mL(-1) and did not change during the experiment. The relative abundance of AM mRNA was placental cotyledons >> lung > cerebral cortex approximately equal to renal cortex > left ventricle approximately equal to right ventricle > adrenal gland > renal medulla > aorta approximately equal to liver. Immunohistochemical staining for AM confirmed distinct labelling in organs with significant expression. AM mRNA level increased significantly in cerebral cortex of hypoxic fetuses. CONCLUSION Our results show expression of AM in placenta and in several fetal organs in late gestation sheep. AM may participate in the cerebral vasodilatation that is an integral part of the fetal response to hypoxia.
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Affiliation(s)
- R I Jensen
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark
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Abstract
Our purpose was to determine how the central haemophagous region and cellular haemomonochorial labyrinth of the tenrec placenta are formed. The haemophagous region is preceded by a region of invasion of the endometrium by trophoblast comprising a cytotrophoblast layer covered by syncytial trophoblast and contiguous with numerous masses of multinucleate trophoblast. The trophoblast intrudes into the endometrium, eliminating the stroma, although small vessels and clumps of glandular epithelium persist. This extensive central region is connected to the forming disk by a ring of chorioallantois covered by a single layer of columnar trophoblast. Later the multinucleate masses and syncytial trophoblast degenerate. The unilaminar cytotrophoblast remains, is elaborated into folds, and phagocytoses glandular secretion, cell debris and erythrocytes. As the central area is transforming, fetal capillaries move into the cytotrophoblast pads surrounding the central zone. Prior to this, the cytotrophoblast has formed a multilayered structure and interrupted maternal vessels to create an anastomotic network of blood spaces lined by cytotrophoblast. The invasion of fetal capillaries transforms this preplacental pad into a cellular haemomonochorial labyrinth with the uninvaded portion forming an underlying spongy zone. Thus interaction of the trophoblast with the endometrium is substantially different in the central zone compared to the area of the preplacental pad.
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Affiliation(s)
- A M Carter
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark.
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Carter AM, Kingston MJ, Han KK, Mazzuca DM, Nygard K, Han VKM. Altered expression of IGFs and IGF-binding proteins during intrauterine growth restriction in guinea pigs. J Endocrinol 2005; 184:179-89. [PMID: 15642794 DOI: 10.1677/joe.1.05781] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The IGF system is one of the most important endocrine and paracrine growth factor systems that regulate fetal and placental growth. We hypothesized that intrauterine growth restriction (IUGR) in guinea pigs is mediated by the altered expression of IGFs and/or IGF binding protein (BP) mRNAs in tissues and is related to growth of specific tissues. IUGR was induced by unilateral uterine artery ligation on day 30 of gestation, and fetal plasma, amniotic fluid and tissue samples were collected at 55-57 days (term about 68 days) from paired IUGR and control fetuses (n=6). Western ligand blotting and immunoblotting were used to compare IGFBP levels in plasma and amniotic fluid. Total RNA was extracted from placenta and fetal tissues, and the relative abundance of IGF-II and IGFBP-1-6 mRNA was determined by Northern blotting, using species-specific probes where available. IUGR fetuses had decreased (P<0.01, by Student's t-test) placental weight and body weight with an increase in the brain:liver weight ratio. The principal IGFBPs in fetal plasma migrated at 40-35, 30 and 25 kDa and were identified as IGFBP-3, -2 and -4 respectively. IUGR was associated with elevated plasma IGFBP-2 and IGFBP-4 and reduced IGFBP-3 levels. IGFBPs were detected at low levels in amniotic fluid of control fetuses but at higher levels in IUGR fetuses. In IUGR placentae, there was a small increase in IGFBP-4 mRNA (P<0.05). IGFBP-2 mRNA increased (P<0.001) in liver of IUGR fetuses. IGF-II and IGFBP mRNA expression did not change in fetal muscle. The results are consistent with reduced IGF action, directly or through inhibition by IGFBPs, particularly by circulating and tissue IGFBP-2, as a potential causal factor in decreased growth of the placenta and certain fetal tissues.
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Affiliation(s)
- A M Carter
- Child Health Research Institute, University of Western Ontario, London, Ontario N6C 2V5, Canada
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Abstract
The four-toed elephant shrew is the only extant member of the genus Petrodromus. Some features of its placentation are found in other elephant shrews and may be important in consolidating the elephant shrews in the order Macroscelidea. These include implantation in an embryo chamber at the caudal end of the uterine horn; a large yolk sac; a large, lobulated allantoic sac; a distinct layer of proliferative trophoblastic cells between the labyrinthine and spongy zones of the placenta; an accessory epitheliochorial placenta; and the formation of a mesoplacenta by the decidua basalis. Of particular note are the large granulated cells that occupy the walls of decidual, myometrial and mesometrial arteries. They appear to be uterine natural killer cells. The persistence of a relatively large yolk sac and a large lobulated allantoic sac is a feature which Petrodromus and other elephant shrews share with other members of the superordinal clade Afrotheria.
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Affiliation(s)
- D Oduor-Okelo
- Department of Veterinary Anatomy, University of Nairobi, Kenya
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Abstract
Afrotheria, one of four mammalian superorders, comprises elephants, sea cows, hyraxes, aardvark, elephant shrews, tenrecs and golden moles. Their placentas either form an equatorial band or are discoid in shape. The interhemal region, separating fetal and maternal blood, is endotheliochorial in elephants, aardvark and possibly the sea cows, but hemochorial in the remaining orders. There is a secondary epitheliochorial placenta in elephant shrews while a similar structure in tenrecs erodes maternal tissues. Specialized hemophagous regions are a striking characteristic of some of these placentas yet absent in hyraxes, elephant shrews, and golden moles. It is possible that the common ancestor of the Afrotheria had an endotheliochorial placenta. Establishment of a hemochorial condition, as seen in rock hyraxes, elephant shrews, tenrecs, and golden moles, would be a more recent development. The elephant, manatee, and aardvark all have circumferential placentas. Thus the formation of a discoid placenta with a more or less extensive secondary placenta in elephant shrews and tenrecs would also be a derived state.
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Affiliation(s)
- A M Carter
- Department of Physiology and Pharmacology, University of Southern Denmark, Winsloewparken 21, Third Floor, DK-5000 Odense, Denmark.
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