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Marzec M, Piórkowski A, Gertych A. Efficient automatic 3D segmentation of cell nuclei for high-content screening. BMC Bioinformatics 2022; 23:203. [PMID: 35641922 DOI: 10.1186/s12859-022-04737-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 05/17/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND High-content screening (HCS) is a pre-clinical approach for the assessment of drug efficacy. On modern platforms, it involves fluorescent image capture using three-dimensional (3D) scanning microscopy. Segmentation of cell nuclei in 3D images is an essential prerequisite to quantify captured fluorescence in cells for screening. However, this segmentation is challenging due to variabilities in cell confluency, drug-induced alterations in cell morphology, and gradual degradation of fluorescence with the depth of scanning. Despite advances in algorithms for segmenting nuclei for HCS, robust 3D methods that are insensitive to these conditions are still lacking. RESULTS We have developed an algorithm which first generates a 3D nuclear mask in the original images. Next, an iterative 3D marker-controlled watershed segmentation is applied to downsized images to segment adjacent nuclei under the mask. In the last step, borders of segmented nuclei are adjusted in the original images based on local nucleus and background intensities. The method was developed using a set of 10 3D images. Extensive tests on a separate set of 27 3D images containing 2,367 nuclei demonstrated that our method, in comparison with 6 reference methods, achieved the highest precision (PR = 0.97), recall (RE = 0.88) and F1-score (F1 = 0.93) of nuclei detection. The Jaccard index (JI = 0.83), which reflects the accuracy of nuclei delineation, was similar to that yielded by all reference approaches. Our method was on average more than twice as fast as the reference method that produced the best results. Additional tests carried out on three stacked 3D images comprising heterogenous nuclei yielded average PR = 0.96, RE = 0.84, F1 = 0.89, and JI = 0.80. CONCLUSIONS The high-performance metrics yielded by the proposed approach suggest that it can be used to reliably delineate nuclei in 3D images of monolayered and stacked cells exposed to cytotoxic drugs.
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Affiliation(s)
- Mariusz Marzec
- Faculty of Science and Technology, Institute of Biomedical Engineering, University of Silesia, Bedzinska St. 39, 41-200, Sosnowiec, Poland.
| | - Adam Piórkowski
- Department of Biocybernetics and Biomedical Engineering, AGH University of Science and Technology, Mickiewicza 30, 30-059, Cracow, Poland
| | - Arkadiusz Gertych
- Department of Surgery, Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA.,Faculty of Biomedical Engineering, Silesian University of Technology, Roosvelta 40, 41-800, Zabrze, Poland
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2
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Ioghen O, Chițoiu L, Gherghiceanu M, Ceafalan LC, Hinescu ME. CD36 - A novel molecular target in the neurovascular unit. Eur J Neurosci 2021; 53:2500-2510. [PMID: 33560561 PMCID: PMC8247892 DOI: 10.1111/ejn.15147] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/12/2021] [Accepted: 01/29/2021] [Indexed: 02/06/2023]
Abstract
CD36 is an integral membrane protein primarily known for its function as a fatty acid transporter, yet also playing other biological roles from lipid metabolism to inflammation modulation. These pleiotropic effects are explained by the existence of multiple different ligands and the extensive distribution in numerous cell types. Moreover, the receptor is related to various pathologies and it may prove to be a good target for prospective therapeutic strategies. In the neurovascular unit (NVU), CD36 is expressed in cells like microglia, microvascular endothelial cells, astrocytes and neurons. In the normal brain, CD36 was proven to be involved in phagocytosis of apoptotic cells, oro‐sensory detection of dietary lipids, and fatty acid transport across the blood brain barrier (BBB). CD36 was also acknowledged as a potentially important player in central nervous system (CNS) disorders, such as Alzheimer Disease‐associated vascular dysfunction and oxidative stress and the neuroinflammatory response in stroke. Despite continuous efforts, the therapeutic arsenal for such diseases is still scarce and there is an increasing interest in discovering new molecular targets for more specific therapeutic approaches. In this review, we summarize the role of CD36 in the normal function of the NVU and in several CNS disorders, focusing on the dysregulation of the NVU and the potential therapeutic modulation.
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Affiliation(s)
- Octavian Ioghen
- Ultrastructural Pathology and Bioimaging Laboratory, Victor Babes Institute of Pathology, Bucharest, Romania
| | - Leona Chițoiu
- Ultrastructural Pathology and Bioimaging Laboratory, Victor Babes Institute of Pathology, Bucharest, Romania
| | - Mihaela Gherghiceanu
- Ultrastructural Pathology and Bioimaging Laboratory, Victor Babes Institute of Pathology, Bucharest, Romania.,Department of Cellular and Molecular Biology and Histology, School of Medicine, Carol Davila Faculty of Medicine, Bucharest, Romania
| | - Laura Cristina Ceafalan
- Department of Cellular and Molecular Biology and Histology, School of Medicine, Carol Davila Faculty of Medicine, Bucharest, Romania.,Cell Biology, Neurosciences and Experimental Myology Laboratory, Victor Babes Institute of Pathology, Bucharest, Romania
| | - Mihail Eugen Hinescu
- Department of Cellular and Molecular Biology and Histology, School of Medicine, Carol Davila Faculty of Medicine, Bucharest, Romania.,Cell Biology, Neurosciences and Experimental Myology Laboratory, Victor Babes Institute of Pathology, Bucharest, Romania
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3
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Pilcher W, Yang X, Zhurikhina A, Chernaya O, Xu Y, Qiu P, Tsygankov D. Shape-to-graph mapping method for efficient characterization and classification of complex geometries in biological images. PLoS Comput Biol 2020; 16:e1007758. [PMID: 32881897 PMCID: PMC7494120 DOI: 10.1371/journal.pcbi.1007758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/16/2020] [Accepted: 07/16/2020] [Indexed: 11/18/2022] Open
Abstract
With the ever-increasing quality and quantity of imaging data in biomedical research comes the demand for computational methodologies that enable efficient and reliable automated extraction of the quantitative information contained within these images. One of the challenges in providing such methodology is the need for tailoring algorithms to the specifics of the data, limiting their areas of application. Here we present a broadly applicable approach to quantification and classification of complex shapes and patterns in biological or other multi-component formations. This approach integrates the mapping of all shape boundaries within an image onto a global information-rich graph and machine learning on the multidimensional measures of the graph. We demonstrated the power of this method by (1) extracting subtle structural differences from visually indistinguishable images in our phenotype rescue experiments using the endothelial tube formations assay, (2) training the algorithm to identify biophysical parameters underlying the formation of different multicellular networks in our simulation model of collective cell behavior, and (3) analyzing the response of U2OS cell cultures to a broad array of small molecule perturbations. In this paper, we present a methodology that is based on mapping an arbitrary set of outlines onto a complete, strictly defined structure, in which every point representing the shape becomes a terminal point of a global graph. Because this mapping preserves the whole complexity of the shape, it allows for extracting the full scope of geometric features of any scale. Importantly, an extensive set of graph-based metrics in each image makes integration with machine learning routines highly efficient even for a small data sets and provide an opportunity to backtrack the subtle morphological features responsible for the automated distinction into image classes. The resulting tool provides efficient, versatile, and robust quantification of complex shapes and patterns in experimental images.
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Affiliation(s)
- William Pilcher
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Xingyu Yang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Anastasia Zhurikhina
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Olga Chernaya
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Yinghan Xu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Peng Qiu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Denis Tsygankov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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4
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Harris C, Pearson K, Hadley K, Zhu S, Browd S, Hanak BW, Shain W. Fabrication of three-dimensional hydrogel scaffolds for modeling shunt failure by tissue obstruction in hydrocephalus. Fluids Barriers CNS 2015; 12:26. [PMID: 26578355 PMCID: PMC4650346 DOI: 10.1186/s12987-015-0023-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/27/2015] [Indexed: 01/19/2023] Open
Abstract
Background Shunt obstruction in the treatment of hydrocephalus is poorly understood, is multi-factorial, and in many cases is modeled ineffectively. Several mechanisms may be responsible, one of which involves shunt infiltration by reactive cells from the brain parenchyma. This has not been modeled in culture and cannot be consistently examined in vivo without a large sample size. Methods We have developed and tested a three-dimensional in vitro model of astrocyte migration and proliferation around clinical grade ventricular catheters and into catheter holes that mimics the development of cellular outgrowth from the parenchyma that may contribute to shunt obstruction. Results Cell attachment and growth was observed on shunt catheters for as long as 80 days with at least 77 % viability until 51 days. The model can be used to study cellular attachment to ventricular catheters under both static and pulsatile flow conditions, which better mimic physiological cerebrospinal fluid dynamics and shunt system flow rates (0.25 mL/min, 100 pulses/min). Pulsatile flow through the ventricular catheter decreased cell attachment/growth by 63 % after 18 h. Under both conditions it was possible to observe cells accumulating around and in shunt catheter holes. Conclusions Alone or in combination with previously-published culture models of shunt obstruction, this model serves as a relevant test bed to analyze mechanisms of shunt failure and to test catheter modifications that will prevent cell attachment and growth.
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Affiliation(s)
- Carolyn Harris
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA. .,Department of Neurosurgery, Wayne State University, 3901 Beaubien Blvd, 2nd Floor Carls Building, Detroit, MI, 48201, USA.
| | - Kelsie Pearson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA.
| | - Kristen Hadley
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA.
| | - Shanshan Zhu
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA.
| | - Samuel Browd
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA. .,Department of Neurological Surgery, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
| | - Brian W Hanak
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA. .,Department of Neurological Surgery, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
| | - William Shain
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA. .,Department of Neurological Surgery, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
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5
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Gertych A, Ma Z, Tajbakhsh J, Velásquez-Vacca A, Knudsen BS. Rapid 3-D delineation of cell nuclei for high-content screening platforms. Comput Biol Med 2015; 69:328-38. [PMID: 25982066 DOI: 10.1016/j.compbiomed.2015.04.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 04/08/2015] [Accepted: 04/16/2015] [Indexed: 12/17/2022]
Abstract
High-resolution three-dimensional (3-D) microscopy combined with multiplexing of fluorescent labels allows high-content analysis of large numbers of cell nuclei. The full automation of 3-D screening platforms necessitates image processing algorithms that can accurately and robustly delineate nuclei in images with little to no human intervention. Imaging-based high-content screening was originally developed as a powerful tool for drug discovery. However, cell confluency, complexity of nuclear staining as well as poor contrast between nuclei and background result in slow and unreliable 3-D image processing and therefore negatively affect the performance of studying a drug response. Here, we propose a new method, 3D-RSD, to delineate nuclei by means of 3-D radial symmetries and test it on high-resolution image data of human cancer cells treated by drugs. The nuclei detection performance was evaluated by means of manually generated ground truth from 2351 nuclei (27 confocal stacks). When compared to three other nuclei segmentation methods, 3D-RSD possessed a better true positive rate of 83.3% and F-score of 0.895±0.045 (p-value=0.047). Altogether, 3D-RSD is a method with a very good overall segmentation performance. Furthermore, implementation of radial symmetries offers good processing speed, and makes 3D-RSD less sensitive to staining patterns. In particular, the 3D-RSD method performs well in cell lines, which are often used in imaging-based HCS platforms and are afflicted by nuclear crowding and overlaps that hinder feature extraction.
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Affiliation(s)
- Arkadiusz Gertych
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
| | - Zhaoxuan Ma
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jian Tajbakhsh
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | | | - Beatrice S Knudsen
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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6
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Hindle P, Hall AC, Biant LC. Viability of chondrocytes seeded onto a collagen I/III membrane for matrix-induced autologous chondrocyte implantation. J Orthop Res 2014; 32:1495-502. [PMID: 25088008 DOI: 10.1002/jor.22701] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/30/2014] [Indexed: 02/04/2023]
Abstract
Cell viability is crucial for effective cell-based cartilage repair. The aim of this study was to determine the effect of handling the membrane during matrix-induced autologous chondrocyte implantation surgery on the viability of implanted chondrocytes. Images were acquired under five conditions: (i) Pre-operative; (ii) Handled during surgery; (iii) Cut edge; (iv) Thumb pressure applied; (v) Heavily grasped with forceps. Live and dead cell stains were used. Images were obtained for cell counting and morphology. Mean cell density was 6.60 × 10(5) cells/cm(2) (5.74-7.11 × 10(5) ) in specimens that did not have significant trauma decreasing significantly in specimens that had been grasped with forceps (p < 0.001) or cut (p = 0.004). Cell viability on delivery grade membrane was 75.1%(72.4-77.8%). This dropped to 67.4%(64.1-69.7%) after handling (p = 0.002), 56.3%(51.5-61.6%) after being thumbed (p < 0.001) and 28.8%(24.7-31.2%) after crushing with forceps (p < 0.001). When cut with scissors there was a band of cell death approximately 275 µm in width where cell viability decreased to 13.7%(10.2-18.2%, p < 0.001). Higher magnification revealed cells without the typical rounded appearance of chondrocytes. We found that confocal laser-scanning microscope (CLSM) can be used to quantify and image the fine morphology of cells on a matrix-induced autologous chondrocyte implantation (MACI) membrane. Careful handling of the membrane is essential to minimise chondrocyte death during surgery.
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Affiliation(s)
- Paul Hindle
- Department of Trauma and Orthopaedic Surgery, The Royal Infirmary of Edinburgh, Edinburgh, The United Kingdom; Centre for Integrative Physiology, School of Biomedical Sciences, The University of Edinburgh, Edinburgh, Edinburgh, The United Kingdom
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7
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Han D, Zhang S, Fan B, Wen LL, Sun M, Zhang H, Feng J. Ischemic postconditioning protects the neurovascular unit after focal cerebral ischemia/reperfusion injury. J Mol Neurosci 2013; 53:50-8. [PMID: 24337985 DOI: 10.1007/s12031-013-0196-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/26/2013] [Indexed: 11/26/2022]
Abstract
Recently, cerebral ischemic postconditioning (Postcond) has been shown to reduce infarction volume in cerebral ischemia/reperfusion (I/R) injury. However, it is unclear if ischemic Postcond offers more extensive neuroprotection than current therapies. The aim of this study was to investigate the neuroprotective effects of ischemic Postcond on the neurovascular unit (NVU). A middle cerebral artery occlusion rat model was used; cerebral infarct volumes, neurologic scores, and transmission electron microscopy were evaluated 24 h after reperfusion. We used Evans blue extravasation, immunohistochemistry, and Western blot analyses to evaluate the integrity of the blood brain barrier (BBB) and the distribution and expression of the tight junction (TJ)-associated proteins of claudin-5 and occludin in brain microvessel endothelium. The Postcond group showed significantly reduced infarct volumes and decreased neurologic impairment scores compared to the I/R group. Also, injuries to the cerebral microvascular endothelial cells, astrocytes, and neurons were minimized in the Postcond group. The permeability of the BBB increased in both the I/R and Postcond groups, but the Postcond group showed a significant decrease in permeability than the I/R group. Expression of both claudin-5 and occludin were higher in the Postcond groups compared to the I/R group, but expression of both proteins decreased in the I/R and Postcond groups compared to the sham group. The results of our study suggest that ischemic Postcond is an effective way to reduce injury to neurons, astrocytes, and endothelial cells, to increase protein expressions of TJ-associated proteins, and to improve BBB intergrity affected by focal I/R. Ischemic Postcond could protect the NVU from I/R injury.
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Affiliation(s)
- Dong Han
- Department of Neurology, The Affiliated Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China
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Strategies for implementing hardware-assisted high-throughput cellular image analysis. ACTA ACUST UNITED AC 2011; 16:422-30. [PMID: 22093299 DOI: 10.1016/j.jala.2011.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Indexed: 11/22/2022]
Abstract
Recent advances in imaging technology for biomedicine, including high-speed microscopy, automated microscopy, and imaging flow cytometry are poised to have a large impact on clinical diagnostics, drug discovery, and biological research. Enhanced acquisition speed, resolution, and automation of sample handling are enabling researchers to probe biological phenomena at an increasing rate and achieve intuitive image-based results. However, the rich image sets produced by these tools are massive, possessing potentially millions of frames with tremendous depth and complexity. As a result, the tools introduce immense computational requirements, and, more importantly, the fact that image analysis operates at a much lower speed than image acquisition limits its ability to play a role in critical tasks in biomedicine such as real-time decision making. In this work, we present our strategy for high-throughput image analysis on a graphical processing unit platform. We scrutinized our original algorithm for detecting, tracking, and analyzing cell morphology in high-speed images and identified inefficiencies in image filtering and potential shortcut routines in the morphological analysis stage. Using our "grid method" for image enhancements resulted in an 8.54× reduction in total run time, whereas origin centering allowed using a look up table for coordinate transformation, which reduced the total run time by 55.64×. Optimization of parallelization and implementation of specialized image processing hardware will ultimately enable real-time analysis of high-throughput image streams and bring wider adoption of assays based on new imaging technologies.
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Amin AK, Huntley JS, Patton JT, Brenkel IJ, Simpson AHRW, Hall AC. Hyperosmolarity protects chondrocytes from mechanical injury in human articular cartilage. ACTA ACUST UNITED AC 2011; 93:277-84. [DOI: 10.1302/0301-620x.93b2.24977] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of this study was to determine whether exposure of human articular cartilage to hyperosmotic saline (0.9%, 600 mOsm) reduces in situ chondrocyte death following a standardised mechanical injury produced by a scalpel cut compared with the same assault and exposure to normal saline (0.9%, 285 mOsm). Human cartilage explants were exposed to normal (control) and hyperosmotic 0.9% saline solutions for five minutes before the mechanical injury to allow in situ chondrocytes to respond to the altered osmotic environment, and incubated for a further 2.5 hours in the same solutions following the mechanical injury. Using confocal laser scanning microscopy, we identified a sixfold (p = 0.04) decrease in chondrocyte death following mechanical injury in the superficial zone of human articular cartilage exposed to hyperosmotic saline compared with normal saline. These data suggest that increasing the osmolarity of joint irrigation solutions used during open and arthroscopic articular surgery may reduce chondrocyte death from surgical injury and could promote integrative cartilage repair.
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Affiliation(s)
- A. K. Amin
- Department of Orthopaedic and Trauma Surgery
| | - J. S. Huntley
- Department of Orthopaedic and Trauma, Surgery Royal Hospital for Sick Children, Dalnair Street, Glasgow G3 8SJ, UK
| | | | - I. J. Brenkel
- Department of Orthopaedic and Trauma Surgery, Queen Margaret Hospital, Whitefield Road, Dunfermline KY12 0SU, UK
| | | | - A. C. Hall
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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Increasing the osmolarity of joint irrigation solutions may avoid injury to cartilage: a pilot study. Clin Orthop Relat Res 2010; 468:875-84. [PMID: 19641975 PMCID: PMC2816775 DOI: 10.1007/s11999-009-0983-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 06/30/2009] [Indexed: 01/31/2023]
Abstract
Saline (0.9%, 285 mOsm) and Hartmann's solution (255 mOsm) are two commonly used joint irrigation solutions that alter the extracellular osmolarity of in situ chondrocytes during articular surgery. We asked whether varying the osmolarity of these solutions influences in situ chondrocyte death in mechanically injured articular cartilage. We initially exposed osteochondral tissue harvested from the metacarpophalangeal joints of 3-year-old cows to solutions of 0.9% saline and Hartmann's solution of different osmolarity (100-600 mOsm) for 2 minutes to allow in situ chondrocytes to respond to the altered osmotic environment. The full thickness of articular cartilage then was "injured" with a fresh scalpel. Using confocal laser scanning microscopy, in situ chondrocyte death at the injured cartilage edge was quantified spatially as a function of osmolarity at 2.5 hours. Increasing the osmolarity of 0.9% saline and Hartmann's solution to 600 mOsm decreased in situ chondrocyte death in the superficial zone of injured cartilage. Compared with 0.9% saline, Hartmann's solution was associated with greater chondrocyte death in the superficial zone of injured cartilage, but not when the osmolarity of both solutions was increased to 600 mOsm. These experiments may have implications for the design of irrigation solutions used during arthroscopic and open articular surgery.
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Amin AK, Huntley JS, Bush PG, Simpson AHRW, Hall AC. Chondrocyte death in mechanically injured articular cartilage--the influence of extracellular calcium. J Orthop Res 2009; 27:778-84. [PMID: 19030171 DOI: 10.1002/jor.20809] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Calcium is thought to be an important regulator of chondrocyte death associated with articular cartilage injury. Our objective was to determine the influence of extracellular calcium on chondrocyte death following mechanical injury. Using a surgically relevant model of sharp mechanical injury (with a scalpel) and confocal laser scanning microscopy (CLSM), in situ chondrocyte death was quantified within the full thickness of articular cartilage as a function of medium calcium concentration and time (2.5 h and 7 days). Exposure of articular cartilage to calcium-free media (approximately 0 mM) significantly reduced superficial zone chondrocyte death after mechanical injury compared with exposure to calcium-rich media (2-20 mM, ANOVA at 2.5 h, p = 0.002). In calcium-rich media, although the extent of chondrocyte death increased with increasing medium calcium concentration, cell death remained localized to the superficial zone of articular cartilage over 7 days (ANOVA, p < 0.05). However, in calcium-free media, there was an increase in chondrocyte death within deeper zones of articular cartilage over 7 days. The early (within hours) chondroprotective effect in calcium-free media suggests that the use of joint irrigation solutions without added calcium may decrease chondrocyte death from mechanical injury during articular surgery. The delayed (within days) increase in chondrocyte death in calcium-free media supports the use of calcium supplementation in media used during cartilage culture for tissue engineering or transplantation.
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Affiliation(s)
- Anish K Amin
- Department of Orthopaedic and Trauma Surgery, University of Edinburgh, Old Dalkeith Road, Edinburgh EH16 4SU, Scotland, United Kingdom.
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Amin AK, Huntley JS, Simpson AHRW, Hall AC. Chondrocyte survival in articular cartilage. ACTA ACUST UNITED AC 2009; 91:691-9. [DOI: 10.1302/0301-620x.91b5.21544] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of this study was to determine whether subchondral bone influences in situ chondrocyte survival. Bovine explants were cultured in serum-free media over seven days with subchondral bone excised from articular cartilage (group A), subchondral bone left attached to articular cartilage (group B), and subchondral bone excised but co-cultured with articular cartilage (group C). Using confocal laser scanning microscopy, fluorescent probes and biochemical assays, in situ chondrocyte viability and relevant biophysical parameters (cartilage thickness, cell density, culture medium composition) were quantified over time (2.5 hours vs seven days). There was a significant increase in chondrocyte death over seven days, primarily within the superficial zone, for group A, but not for groups B or C (p < 0.05). There was no significant difference in cartilage thickness or cell density between groups A, B and C (p > 0.05). Increases in the protein content of the culture media for groups B and C, but not for group A, suggested that the release of soluble factors from subchondral bone may have influenced chondrocyte survival. In conclusion, subchondral bone significantly influenced chondrocyte survival in articular cartilage during explant culture. The extrapolation of bone-cartilage interactions in vitro to the clinical situation must be made with caution, but the findings from these experiments suggest that future investigation into in vivo mechanisms of articular cartilage survival and degradation must consider the interactions of cartilage with subchondral bone.
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Affiliation(s)
- A. K. Amin
- Department of Orthopaedic and Trauma Surgery, University of Edinburgh, Old Dalkeith Road, Edinburgh EH16 4SU, UK
| | - J. S. Huntley
- Department of Orthopaedic and Trauma Surgery, University of Edinburgh, Old Dalkeith Road, Edinburgh EH16 4SU, UK
| | - A. H. R. W. Simpson
- Department of Orthopaedic and Trauma Surgery, University of Edinburgh, Old Dalkeith Road, Edinburgh EH16 4SU, UK
| | - A. C. Hall
- Centre for Integrative Physiology, School of Biomedical Sciences Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, UK
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Shen Q, Wang Y, Kokovay E, Lin G, Chuang SM, Goderie SK, Roysam B, Temple S. Adult SVZ stem cells lie in a vascular niche: a quantitative analysis of niche cell-cell interactions. Cell Stem Cell 2008; 3:289-300. [PMID: 18786416 DOI: 10.1016/j.stem.2008.07.026] [Citation(s) in RCA: 781] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 05/02/2008] [Accepted: 07/29/2008] [Indexed: 11/26/2022]
Abstract
There is an emerging understanding of the importance of the vascular system within stem cell niches. Here, we examine whether neural stem cells (NSCs) in the adult subventricular zone (SVZ) lie close to blood vessels, using three-dimensional whole mounts, confocal microscopy, and automated computer-based image quantification. We found that the SVZ contains a rich plexus of blood vessels that snake along and within neuroblast chains. Cells expressing stem cell markers, including GFAP, and proliferation markers are closely apposed to the laminin-containing extracellular matrix (ECM) surrounding vascular endothelial cells. Apical GFAP+ cells are admixed within the ependymal layer and some span between the ventricle and blood vessels, occupying a specialized microenvironment. Adult SVZ progenitor cells express the laminin receptor alpha6beta1 integrin, and blocking this inhibits their adhesion to endothelial cells, altering their position and proliferation in vivo, indicating that it plays a functional role in binding SVZ stem cells within the vascular niche.
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Affiliation(s)
- Qin Shen
- New York Neural Stem Cell Institute, Rensselaer, NY 12144, USA
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14
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Zhang Y, Zhou X, Lu J, Lichtman J, Adjeroh D, Wong STC. 3D Axon structure extraction and analysis in confocal fluorescence microscopy images. Neural Comput 2008; 20:1899-927. [PMID: 18336075 DOI: 10.1162/neco.2008.05-07-519] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The morphological properties of axons, such as their branching patterns and oriented structures, are of great interest for biologists in the study of the synaptic connectivity of neurons. In these studies, researchers use triple immunofluorescent confocal microscopy to record morphological changes of neuronal processes. Three-dimensional (3D) microscopy image analysis is then required to extract morphological features of the neuronal structures. In this article, we propose a highly automated 3D centerline extraction tool to assist in this task. For this project, the most difficult part is that some axons are overlapping such that the boundaries distinguishing them are barely visible. Our approach combines a 3D dynamic programming (DP) technique and marker-controlled watershed algorithm to solve this problem. The approach consists of tracking and updating along the navigation directions of multiple axons simultaneously. The experimental results show that the proposed method can rapidly and accurately extract multiple axon centerlines and can handle complicated axon structures such as cross-over sections and overlapping objects.
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Affiliation(s)
- Yong Zhang
- Center of Biomedical Informatics, Department of Radiology, The Methodist Hospital Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA.
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15
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Bjornsson CS, Lin G, Al-Kofahi Y, Narayanaswamy A, Smith KL, Shain W, Roysam B. Associative image analysis: a method for automated quantification of 3D multi-parameter images of brain tissue. J Neurosci Methods 2008; 170:165-78. [PMID: 18294697 DOI: 10.1016/j.jneumeth.2007.12.024] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 12/06/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022]
Abstract
Brain structural complexity has confounded prior efforts to extract quantitative image-based measurements. We present a systematic 'divide and conquer' methodology for analyzing three-dimensional (3D) multi-parameter images of brain tissue to delineate and classify key structures, and compute quantitative associations among them. To demonstrate the method, thick ( approximately 100 microm) slices of rat brain tissue were labeled using three to five fluorescent signals, and imaged using spectral confocal microscopy and unmixing algorithms. Automated 3D segmentation and tracing algorithms were used to delineate cell nuclei, vasculature, and cell processes. From these segmentations, a set of 23 intrinsic and 8 associative image-based measurements was computed for each cell. These features were used to classify astrocytes, microglia, neurons, and endothelial cells. Associations among cells and between cells and vasculature were computed and represented as graphical networks to enable further analysis. The automated results were validated using a graphical interface that permits investigator inspection and corrective editing of each cell in 3D. Nuclear counting accuracy was >89%, and cell classification accuracy ranged from 81 to 92% depending on cell type. We present a software system named FARSIGHT implementing our methodology. Its output is a detailed XML file containing measurements that may be used for diverse quantitative hypothesis-driven and exploratory studies of the central nervous system.
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Affiliation(s)
- Christopher S Bjornsson
- Center for Neural Communication Technology, New York State Department of Health, Wadsworth Center, Albany, NY 12201-0509, USA
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16
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Lin G, Chawla MK, Olson K, Barnes CA, Guzowski JF, Bjornsson C, Shain W, Roysam B. A multi-model approach to simultaneous segmentation and classification of heterogeneous populations of cell nuclei in 3D confocal microscope images. Cytometry A 2007; 71:724-36. [PMID: 17654650 DOI: 10.1002/cyto.a.20430] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Automated segmentation and morphometry of fluorescently labeled cell nuclei in batches of 3D confocal stacks is essential for quantitative studies. Model-based segmentation algorithms are attractive due to their robustness. Previous methods incorporated a single nuclear model. This is a limitation for tissues containing multiple cell types with different nuclear features. Improved segmentation for such tissues requires algorithms that permit multiple models to be used simultaneously. This requires a tight integration of classification and segmentation algorithms. Two or more nuclear models are constructed semiautomatically from user-provided training examples. Starting with an initial over-segmentation produced by a gradient-weighted watershed algorithm, a hierarchical fragment merging tree rooted at each object is built. Linear discriminant analysis is used to classify each candidate using multiple object models. On the basis of the selected class, a Bayesian score is computed. Fragment merging decisions are made by comparing the score with that of other candidates, and the scores of constituent fragments of each candidate. The overall segmentation accuracy was 93.7% and classification accuracy was 93.5%, respectively, on a diverse collection of images drawn from five different regions of the rat brain. The multi-model method was found to achieve high accuracy on nuclear segmentation and classification by correctly resolving ambiguities in clustered regions containing heterogeneous cell populations.
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Affiliation(s)
- Gang Lin
- ECSE Department and Center for Subsurface Sensing and Imaging Systems, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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17
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Zinchuk V, Zinchuk O, Okada T. Quantitative colocalization analysis of multicolor confocal immunofluorescence microscopy images: pushing pixels to explore biological phenomena. Acta Histochem Cytochem 2007; 40:101-11. [PMID: 17898874 PMCID: PMC1993886 DOI: 10.1267/ahc.07002] [Citation(s) in RCA: 328] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 06/08/2007] [Indexed: 11/22/2022] Open
Abstract
Quantitative colocalization analysis is an advanced digital imaging tool to examine antigens of interest in immunofluorescence images obtained using confocal microscopes. It employs specialized algorithms to estimate the degree of overlap of fluorescence signals and thus enables acquiring important new information not otherwise obtainable using qualitative approaches alone. As raw confocal images have high levels of background, they should be prepared to become suitable for reliable calculation of colocalization coefficients by correcting it. We provide concise theoretical basis of quantitative colocalization analysis, discuss its limitations, and describe proper use of the technique. The use of quantitative colocalization analysis is demonstrated by studying bile salt export pump and multidrug resistance associated protein 2 in the liver and major basic protein and platelet activating factor receptor antigens in conjunctiva. The review is focused on the applicability and correct interpretation of the results of colocalization coefficients calculations.
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Affiliation(s)
- Vadim Zinchuk
- Department of Anatomy and Cell Biology, Kochi University Faculty of Medicine
| | - Olga Zinchuk
- Department of Ophthalmology, Kochi University Faculty of Medicine, Okoh-cho, Nankoku, Kochi 783–8505, Japan
| | - Teruhiko Okada
- Department of Anatomy and Cell Biology, Kochi University Faculty of Medicine
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18
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Smith CM, Cole Smith J, Williams SK, Rodriguez JJ, Hoying JB. Automatic thresholding of three-dimensional microvascular structures from confocal microscopy images. J Microsc 2007; 225:244-57. [PMID: 17371447 DOI: 10.1111/j.1365-2818.2007.01739.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have combined confocal microscopy, image processing, and optimization techniques to obtain automated, accurate volumetric measurements of microvasculature. Initially, we made tissue phantoms containing 15-microm FocalCheck microspheres suspended in type I collagen. Using these phantoms we obtained a stack of confocal images and examined the accuracy of various thresholding schemes. Thresholding algorithms from the literature that utilize a unimodal histogram, a bimodal histogram, or an intensity and edge-based algorithm all significantly overestimated the volume of foreground structures in the image stack. Instead, we developed a heuristic technique to automatically determine good-quality threshold values based on the depth, intensity, and (optionally) gradient of each voxel. This method analyzed intensity and gradient threshold methods for each individual image stack, taking into account the intensity attenuation that is seen in deeper images of the stack. Finally, we generated a microvascular construct comprised of rat fat microvessel fragments embedded in collagen I gels and obtained stacks of confocal images. Using our new thresholding scheme we were able to obtain automatic volume measurements of growing microvessel fragments.
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Affiliation(s)
- Cynthia M Smith
- Biomedical Engineering Program, University of Arizona, Tucson, Arizona 85724, USA
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19
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20
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Schwartz AB, Cui XT, Weber DJ, Moran DW. Brain-Controlled Interfaces: Movement Restoration with Neural Prosthetics. Neuron 2006; 52:205-20. [PMID: 17015237 DOI: 10.1016/j.neuron.2006.09.019] [Citation(s) in RCA: 412] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brain-controlled interfaces are devices that capture brain transmissions involved in a subject's intention to act, with the potential to restore communication and movement to those who are immobilized. Current devices record electrical activity from the scalp, on the surface of the brain, and within the cerebral cortex. These signals are being translated to command signals driving prosthetic limbs and computer displays. Somatosensory feedback is being added to this control as generated behaviors become more complex. New technology to engineer the tissue-electrode interface, electrode design, and extraction algorithms to transform the recorded signal to movement will help translate exciting laboratory demonstrations to patient practice in the near future.
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Affiliation(s)
- Andrew B Schwartz
- Department of Neurobiology, Center for the Neural Basis of Cognition, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania 15213, USA.
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21
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Ruf F, Park MJ, Hayot F, Lin G, Roysam B, Ge Y, Sealfon SC. Mixed Analog/Digital Gonadotrope Biosynthetic Response to Gonadotropin-releasing Hormone. J Biol Chem 2006; 281:30967-78. [PMID: 16916798 DOI: 10.1074/jbc.m606486200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian reproduction requires gonadotropin-releasing hormone (GnRH)-mediated signaling from brain neurons to pituitary gonadotropes. Because the pulses of released GnRH vary greatly in amplitude, we studied the biosynthetic response of the gonadotrope to varying GnRH concentrations, focusing on extracellular-regulated kinase (ERK) phosphorylation and egr1 mRNA and protein production. The overall average level of ERK activation in populations of cells increased non-cooperatively with increasing GnRH and did not show evidence of either ultrasensitivity or bistability. However, automated image analysis of single-cell responses showed that whereas individual gonadotropes exhibited two response states, inactive and active, both the probability of activation and the average response in activated cells increased with increasing GnRH concentration. These data indicate a hybrid single-cell response having both digital (switch-like) and analog (graded) features. Mathematical modeling suggests that the hybrid response can be explained by indirect thresholding of ERK activation resulting from the distributed structure of the GnRH-modulated network. The hybrid response mechanism improves the reliability of noisy reproductive signal transmission from the brain to the pituitary.
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Affiliation(s)
- Frederique Ruf
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA
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22
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Selinummi J, Sarkanen JR, Niemistö A, Linne ML, Ylikomi T, Yli-Harja O, Jalonen TO. Quantification of vesicles in differentiating human SH-SY5Y neuroblastoma cells by automated image analysis. Neurosci Lett 2006; 396:102-7. [PMID: 16356645 DOI: 10.1016/j.neulet.2005.11.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 09/26/2005] [Accepted: 11/08/2005] [Indexed: 11/23/2022]
Abstract
A new automated image analysis method for quantification of fluorescent dots is presented. This method facilitates counting the number of fluorescent puncta in specific locations of individual cells and also enables estimation of the number of cells by detecting the labeled nuclei. The method is here used for counting the AM1-43 labeled fluorescent puncta in human SH-SY5Y neuroblastoma cells induced to differentiate with all-trans retinoic acid (RA), and further stimulated with high potassium (K+) containing solution. The automated quantification results correlate well with the results obtained manually through visual inspection. The manual method has the disadvantage of being slow, labor-intensive, and subjective, and the results may not be reproducible even in the intra-observer case. The automated method, however, has the advantage of allowing fast quantification with explicitly defined methods, with no user intervention. This ensures objectivity of the quantification. In addition to the number of fluorescent dots, further development of the method allows its use for quantification of several other parameters, such as intensity, size, and shape of the puncta, that are difficult to quantify manually.
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Affiliation(s)
- Jyrki Selinummi
- Institute of Signal Processing, Tampere University of Technology, FIN-33101 Tampere, Finland.
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