1
|
Ngo JP, Le B, Khan Z, Kett MM, Gardiner BS, Smith DW, Melhem MM, Maksimenko A, Pearson JT, Evans RG. Micro-computed tomographic analysis of the radial geometry of intrarenal artery-vein pairs in rats and rabbits: Comparison with light microscopy. Clin Exp Pharmacol Physiol 2017; 44:1241-1253. [PMID: 28795785 DOI: 10.1111/1440-1681.12842] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/01/2017] [Accepted: 08/01/2017] [Indexed: 02/06/2023]
Abstract
We assessed the utility of synchrotron-radiation micro-computed tomography (micro-CT) for quantification of the radial geometry of the renal cortical vasculature. The kidneys of nine rats and six rabbits were perfusion fixed and the renal circulation filled with Microfil. In order to assess shrinkage of Microfil, rat kidneys were imaged at the Australian Synchrotron immediately upon tissue preparation and then post fixed in paraformaldehyde and reimaged 24 hours later. The Microfil shrank only 2-5% over the 24 hour period. All subsequent micro-CT imaging was completed within 24 hours of sample preparation. After micro-CT imaging, the kidneys were processed for histological analysis. In both rat and rabbit kidneys, vascular structures identified in histological sections could be identified in two-dimensional (2D) micro-CT images from the original kidney. Vascular morphology was similar in the two sets of images. Radial geometry quantified by manual analysis of 2D images from micro-CT was consistent with corresponding data generated by light microscopy. However, due to limited spatial resolution when imaging a whole organ using contrast-enhanced micro-CT, only arteries ≥100 and ≥60 μm in diameter, for the rat and rabbit respectively, could be assessed. We conclude that it is feasible and valid to use micro-CT to quantify vascular geometry of the renal cortical circulation in both the rat and rabbit. However, a combination of light microscopic and micro-CT approaches are required to evaluate the spatial relationships between intrarenal arteries and veins over an extensive range of vessel size.
Collapse
Affiliation(s)
- Jennifer P Ngo
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Bianca Le
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Zohaib Khan
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, WA, Australia.,School of Information Technology and Mathematical Sciences, University of South Australia, Adelaide, SA, Australia
| | - Michelle M Kett
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Bruce S Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, WA, Australia
| | - David W Smith
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, WA, Australia
| | - Mayer M Melhem
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Anton Maksimenko
- Imaging and Medical Beamline, Australian Synchrotron, Clayton, Vic., Australia
| | - James T Pearson
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia.,Monash Biomedical Imaging Facility, Monash University, Melbourne, Vic., Australia.,Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| |
Collapse
|
2
|
Hafez S. Comparative Placental Anatomy: Divergent Structures Serving a Common Purpose. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 145:1-28. [PMID: 28110748 DOI: 10.1016/bs.pmbts.2016.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The placenta, one of the most important transient organs, forms by the apposition of fetal membranes and maternal tissues. Its role is to mediate physiological exchanges between mother and fetus. The word "apposition" covers a wide range of structural variations. It includes approximation, adhesion, interdigitation, or actual fusion between fetal and maternal tissues.1 Formation of the placenta establishes hemotropic nutrition for the fetus: essential metabolites must be provided to maintain the growing fetus, and these must come to it via the maternal circulatory system.2,3 Equally important, the placenta also provides oxygen and removes metabolic waste products from fetal blood. Nutritive and excretory roles of the placenta are not its only functions: it also has immune and endocrine activities.4 Nutrient and gas transport, waste removal, immunological protection of the fetus, and hormonal secretion influencing the maternal metabolism are all complex functions. They may also to some extent be conflicting purposes; hence, the placenta is a complex fetal organ. It is structurally adapted to perform its roles somewhat differently in different species, but the set of functions remain the same. Understandably, the placenta has been the subject of extensive research, and it will continue be an important topic thanks to its complexity. The intent of this chapter is to provide a simple description of placental anatomy using classic categories and to describe anatomical species variations in humans, important domestic animals, and the major laboratory species.
Collapse
Affiliation(s)
- S Hafez
- Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States; Virginia Tech Carilion School of Medicine and Research Institute, Roanoke, VA, United States.
| |
Collapse
|
3
|
Hematological and biochemical findings in pregnant, postfoaling, and lactating jennies. Theriogenology 2015; 85:1233-8. [PMID: 26792379 DOI: 10.1016/j.theriogenology.2015.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 12/07/2015] [Accepted: 12/10/2015] [Indexed: 11/22/2022]
Abstract
The aims of this study were to (1) verify if significant changes occur in hematological and biochemical parameters in jennies during the last 2 months of pregnancy and the first 2 months of lactation, and (2) determine any differences with mares. Hematological and biochemical parameters were evaluated in jennies every 15 days during late pregnancy, parturition, and early lactation. The Kolmogorov-Smirnov test, analysis of variance for repeated measurements and Tukey's multiple comparison test as post hoc were applied. The significance level was set at P < 0.05. Statistical analysis showed differences related to time for Red Blood Cells (RBC) count and Hematocrit (HCT), White Blood Cells (WBC) count, platelet count (PLT), total proteins, blood urea, triglycerides and total cholesterol concentrations, aspartate aminotransferase, gamma-glutamyltransferase, creatine-phosphokinase activities, sodium (Na) and potassium (K). RBC and HCT were higher in late pregnancy than at foaling and during lactation. The relative anemia might be due to increased water ingestion because of fluid losses. The WBC count was higher at foaling than during late pregnancy and lactation. This could be related to the release of cortisol and catecholamine during delivery. The PLT trend showed lower values from delivery to the first 2 months of lactation compared to late gestation. Blood urea increased near parturition, and then remained constant during delivery and lactation, which might be due to the high energy demand at the beginning of lactation. Triglycerides and total cholesterol showed a decrease from delivery through the lactation period. Thus, jennies seem to have a similar metabolism of fats to ponies and draft horse mares, characterized by a greater fat content and mobilization than light breed horses. Aspartate aminotransferase activity decreased at parturition and early lactation, probably because of a predominance of anabolic over catabolic processes during pregnancy. Gamma-glutamyltransferase activity was lower at delivery and during lactation than at late gestation. This could be due to a physiological load on the liver in the perinatal period. Gamma-glutamyltransferase activity was always higher than in mares, but within the normal range for adult donkeys. Creatine-phosphokinase decreased near delivery, then was constant from parturition through the first 2 months of lactation. Na decreased during lactation, probably due to an increased renal retention mediated by aldosterone release during pregnancy. K showed the same trend as Na, and concentrations are in line with the species. The higher K during pregnancy may be due to reabsorption by the gut. Total proteins decreased more during the postpartum period and lactation than in the gestational period. In conclusion, our results showed significant changes in hematological and biochemical parameters in jennies during the last 2 months of pregnancy and the first 2 months of lactation and these changes are only partially comparable to mares.
Collapse
|
4
|
Hafez SA, Borowicz P, Reynolds LP, Redmer DA. Maternal and fetal microvasculature in sheep placenta at several stages of gestation. J Anat 2010; 216:292-300. [PMID: 20070427 DOI: 10.1111/j.1469-7580.2009.01184.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi.
Collapse
Affiliation(s)
- Shireen A Hafez
- Department of Anatomy and Embryology, College of Veterinary Medicine, Alexandria University, Elbehera, Egypt
| | | | | | | |
Collapse
|