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Zhai Y, Tian H, Zhang W, Sun S, Zhao Z. Genome-wide analysis of long noncoding RNAs as cis-acting regulators of transcription factor-encoding genes in IgA nephropathy. PLoS One 2024; 19:e0304301. [PMID: 38787831 PMCID: PMC11125480 DOI: 10.1371/journal.pone.0304301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world, but the disease pathogenesis noncoding is yet to be elucidated. Previous studies have revealed regulatory functions for long noncoding RNA (lncRNA) in various diseases; however, the roles of lncRNA in IgAN and regulation of transcription factors (TFs) have been scarcely investigated. METHODS Renal tissue samples (n = 5) from patients with IgAN and control samples (n = 4) were collected and RNA sequencing (RNA-seq) was performed. Four software programs were employed for lncRNA prediction. GO (Gene Ontology)/KEGG (Kyoto Encyclopedia of Genes and Genomes) were employed for analysis of the identified differentially expressed genes (DEGs). A regulatory network model of DE lncRNA-TF-DEG was developed, and the levels of expression of key lncRNAs, TFs, and corresponding target genes were assessed using qRT-PCR and immunofluorescence. RESULTS The current study identified 674 upregulated and 1,011 downregulated DE mRNAs and 260 upregulated and 232 downregulated DE lncRNAs in IgAN samples compared with control samples. The upregulated DE mRNAs showed enrichment in cell adhesion and collagen glial fiber organization pathways. The DE lncRNAs-DE mRNAs showing co-expression are associated with transmembrane transport. A novel regulatory network model of lncRNA-TF-DEG has been developed. This study identified seven TFs that are cis-regulated by 6 DE lncRNAs, and show co-expression with 132 DEGs (correlation coefficient ≥ 0.8, P ≤ 0.01), generating 158 pairs that showed co-expression. The lncRNAs NQO1-DT and RP5-1057120.6 were found to be highly expressed in IgAN samples. The TFs vitamin D Receptor (VDR) and NFAT5, along with their target genes were also aberrantly expressed. CONCLUSION Key lncRNAs and TFs centrally associated with IgAN have been identified in this study. A regulatory network model of lncRNA-TF-mRNA was constructed. Further studies on the genes identified herewith could provide insight into the pathogenesis of IgAN.
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Affiliation(s)
- Yaling Zhai
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Renal Research Institution of Zhengzhou University, Zhengzhou, China
| | - Huijuan Tian
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Renal Research Institution of Zhengzhou University, Zhengzhou, China
| | - Wenhui Zhang
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Renal Research Institution of Zhengzhou University, Zhengzhou, China
| | - Shuaigang Sun
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Renal Research Institution of Zhengzhou University, Zhengzhou, China
| | - Zhanzheng Zhao
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Renal Research Institution of Zhengzhou University, Zhengzhou, China
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Kaller R, Russu E, Arbănași EM, Mureșan AV, Jakab M, Ciucanu CC, Arbănași EM, Suciu BA, Hosu I, Demian L, Horváth E. Intimal CD31-Positive Relative Surfaces Are Associated with Systemic Inflammatory Markers and Maturation of Arteriovenous Fistula in Dialysis Patients. J Clin Med 2023; 12:4419. [PMID: 37445452 DOI: 10.3390/jcm12134419] [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: 05/28/2023] [Revised: 06/25/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND Arteriovenous fistula dysfunction is a widely disputed subject in the scientific literature on end-stage kidney disease (ESKD). The main cause of mortality and morbidity in these patients is the non-maturation or dysfunction of the arteriovenous fistula. Despite the many complications, the native arteriovenous fistula remains the gold standard in the treatment of these patients requiring renal replacement. This study aims to discuss the predictive role of some systemic inflammatory biomarkers (NLR, PLR, SII, IL-6), intimal hyperplasia, and neoangiogenesis (characterized by intimal-media CD31-positive relative surface) in arteriovenous fistula maturation failure. METHODS The present study was designed as an observational, analytical, and prospective study which included patients diagnosed with ESKD with indications of radio-cephalic arteriovenous fistula (RCAVF). Demographic data, comorbidities, preoperative laboratory data and histological/digital morphometry analysis results were processed. The patients included were divided into two groups based on their AVF maturation status at 8 weeks: "Maturation" (Group 1) and "Failed Maturation" (Group 2). RESULTS There was no difference in the demographic data. In terms of comorbidities, the second group had a greater incidence of heart failure (p = 0.03), diabetes (p = 0.04), peripheral artery disease (p = 0.002), and obesity (p = 0.01). Additionally, regarding the laboratory findings, these patients had higher levels of serum uric acid (p = 0.0005), phosphates (p < 0.0001), and creatinine (p = 0.02), as well as lower levels of total calcium (p = 0.0002), monocytes (p = 0.008), and lymphocytes (p < 0.0001). Moreover, all inflammatory markers (p = 0.001; p < 0.0001; p = 0.006, and p = 0.03) and Ca-P product (p < 0.0001) had higher baseline values in Group 2. Upon immunohistochemical analysis, regarding the density of neoformed vessels, there was a higher incidence of CD31-positive surfaces (p = 0.006) and CD31-positive relative surfaces (p = 0.001); the NLR (r = 0.323; p = 0.03), PLR (r = 0.381; p = 0.04), SII (r = 0.376; p = 0.03), and IL-6 (r = 0.611; p < 0.001) are all significantly correlated with vascular density, as evidenced by CD31. CONCLUSIONS Heart failure, peripheral artery disease, obesity, and diabetes, as well as the systemic inflammatory markers (NLR, PLR, SII, IL-6), intimal hyperplasia, and CD31-positive relative surfaces are predictors of arteriovenous fistula maturation failures.
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Affiliation(s)
- Réka Kaller
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Eliza Russu
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Department of Vascular Surgery, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Emil Marian Arbănași
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
- Department of Vascular Surgery, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Adrian Vasile Mureșan
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Department of Vascular Surgery, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Márk Jakab
- Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | | | - Eliza Mihaela Arbănași
- Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Bogdan Andrei Suciu
- Department of Anatomy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Ioan Hosu
- Department of Nephrology, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Liliana Demian
- Center of Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Emőke Horváth
- Department of Pathology, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu Mures, 540139 Targu Mures, Romania
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Zebaze R, Ebeling PR. Disorganization and Musculoskeletal Diseases: Novel Insights into the Enigma of Unexplained Bone Abnormalities and Fragility Fractures. Curr Osteoporos Rep 2022; 21:154-166. [PMID: 36494594 DOI: 10.1007/s11914-022-00759-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/31/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Describe the potential contribution of disorganized tissue to the pathogenesis of bone abnormalities and fractures. Especially, fractures that are unexplained by bone loss (osteoporosis) or structural deterioration. RECENT FINDINGS Currently, bone fragility is primarily viewed as due to loss, or decay (osteoporosis). However, it is also acknowledged that this view is limited because it does not explain many fractures or abnormalities such as necrosis, sclerosis, or infarcts. Atypical femoral fractures (AFFs) during antiresorptive therapy are an example. Hence, it is proposed that another distinct mechanism is responsible for bone diseases. A remarkable bone property distinct from mass and decay is the organization (arrangement) of its components. Components must be perfectly assembled or well-stacked to ensure "the right amount of bone, at the right place". Disorganization is an aberration that is conspicuous in many diseases, more so in conditions poorly associated with bone mass and decay such as osteogenesis imperfecta, hypophosphatasia, and AFFs. However, despite the likely critical role of disorganization, this feature has received limited clinical attention. This review focuses on the potential contribution of disorganization to bone in health and diseases. Particularly, we propose that disorganization, by causing ineffective transfer of loads, may produce not only bone abnormalities (pain, necrosis, infarct, sclerosis, delayed healing) but also fractures, especially AFFs or stress fractures. A disorganized element is one that is where it shouldn't be (improperly stacked elements). Hence, disorganization can be measured by quantifying the extent to which a tissue (pixel within an image) is at an incorrect location.
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Affiliation(s)
- Roger Zebaze
- Department of Medicine, School of Clinical Sciences, Monash University, Level 5, Block E, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria, 3168, Australia.
| | - Peter Robert Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Level 5, Block E, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria, 3168, Australia
- Department of Endocrinology, Monash Health, Clayton, Victoria, Australia
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Role of Collagen in Vascular Calcification. J Cardiovasc Pharmacol 2022; 80:769-778. [PMID: 35998017 DOI: 10.1097/fjc.0000000000001359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 08/03/2022] [Indexed: 12/13/2022]
Abstract
ABSTRACT Vascular calcification is a pathological process characterized by ectopic calcification of the vascular wall. Medial calcifications are most often associated with kidney disease, diabetes, hypertension, and advanced age. Intimal calcifications are associated with atherosclerosis. Collagen can regulate mineralization by binding to apatite minerals and promoting their deposition, binding to collagen receptors to initiate signal transduction, and inducing cell transdifferentiation. In the process of vascular calcification, type I collagen is not only the scaffold for mineral deposition but also a signal entity, guiding the distribution, aggregation, and nucleation of vesicles and promoting the transformation of vascular smooth muscle cells into osteochondral-like cells. In recent years, collagen has been shown to affect vascular calcification through collagen disc-domain receptors, matrix vesicles, and transdifferentiation of vascular smooth muscle cells.
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St. Hilaire C. Medial Arterial Calcification: A Significant and Independent Contributor of Peripheral Artery Disease. Arterioscler Thromb Vasc Biol 2022; 42:253-260. [PMID: 35081727 PMCID: PMC8866228 DOI: 10.1161/atvbaha.121.316252] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over 200 million individuals worldwide are estimated to have peripheral artery disease (PAD). Although the term peripheral can refer to any outer branch of the vasculature, the focus of this review is on lower-extremity arteries. The initial sequelae of PAD often include movement-induced cramping pain in the hips and legs or loss of hair and thinning of the skin on the lower limbs. PAD progresses, sometimes rapidly, to cause nonhealing ulcers and critical limb ischemia which adversely affects mobility and muscle tone; acute limb ischemia is a medical emergency. PAD causes great pain and a high risk of amputation and ultimately puts patients at significant risk for major adverse cardiovascular events. The negative impact on patients' quality of life, as well as the medical costs incurred, are huge. Atherosclerotic plaques are one cause of PAD; however, emerging clinical data now shows that nonatherosclerotic medial arterial calcification (MAC) is an equal and distinct contributor. This ATVB In Focus article will present the recent clinical findings on the prevalence and impact of MAC in PAD, discuss the known pathways that contribute specifically to MAC in the lower extremity, and highlight gaps in knowledge and tools that limit our understanding of MAC pathogenesis.
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Affiliation(s)
- Cynthia St. Hilaire
- Division of Cardiology, Departments of Medicine and Bioengineering, Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, PA
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Labissiere X, Zigmond ZM, Challa A, Montoya C, Manzur-Pineda K, Abraham A, Tabbara M, Salama A, Pan Y, Salman LH, Yang X, Vazquez-Padron RI, Martinez L. Vein morphometry in end-stage kidney disease: Teasing out the contribution of age, comorbidities, and vintage to chronic wall remodeling. Front Cardiovasc Med 2022; 9:1005030. [PMID: 36419492 PMCID: PMC9676677 DOI: 10.3389/fcvm.2022.1005030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
Background Chronic kidney disease (CKD) is a highly comorbid condition with significant effects on vascular health and remodeling. Upper extremity veins are important in end-stage kidney disease (ESKD) due to their potential use to create vascular accesses. However, unlike arteries, the contribution of CKD-associated factors to the chronic remodeling of veins has been barely studied. Methods We measured morphometric parameters in 315 upper extremity veins, 131 (85% basilic) from stage 5 CKD/ESKD patients and 184 (89% basilic) from non-CKD organ donors. Associations of demographic and clinical characteristics with intimal hyperplasia (IH) and medial fibrosis were evaluated using multivariate regression models. Results The study cohort included 33% females, 30% blacks, 32% Hispanics, and 37% whites. Over 60% had hypertension, and 25% had diabetes independent of CKD status. Among kidney disease participants, 26% had stage 5 CKD, while 22 and 52% had ESKD with and without history of a previous arteriovenous fistula/graft (AVF/AVG), respectively. Intimal hyperplasia was associated with older age (β = 0.13 per year, confidence interval [CI] = 0.002-0.26), dialysis vintage > 12 months (β = 0.22, CI = 0.09-0.35), and previous AVF/AVG creation (β = 0.19, CI = 0.06-0.32). Upper quartile values of IH were significantly associated with diabetes (odds ratio [OR] = 2.02, CI = 1.08-3.80), which demonstrated an additive effect with previous AVF/AVG history and longer vintage in exacerbating IH. Medial fibrosis also increased as a function of age (β = 0.17, CI = 0.04-0.30) and among patients with diabetes (β = 0.15, CI = 0.03-0.28). Age was the predominant factor predicting upper quartile values of fibrosis (OR = 1.03 per year, CI = 1.01-1.05) independent of other comorbidities. Conclusion Age and diabetes are the most important risk factors for chronic development of venous IH and fibrosis independent of CKD status. Among kidney disease patients, longer dialysis vintage, and history of a previous AVF/AVG are strong predictors of IH.
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Affiliation(s)
- Xochilt Labissiere
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Zachary M Zigmond
- Bruce W. Carter Veterans Affairs Medical Center, Miami, FL, United States
| | - Akshara Challa
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Christopher Montoya
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Karen Manzur-Pineda
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Amalia Abraham
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Marwan Tabbara
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Alghidak Salama
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Yue Pan
- Department of Public Health Sciences, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Loay H Salman
- Division of Nephrology, Albany Medical College, Albany, NY, United States
| | - Xiaofeng Yang
- Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Roberto I Vazquez-Padron
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.,Bruce W. Carter Veterans Affairs Medical Center, Miami, FL, United States
| | - Laisel Martinez
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States
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Chaimontri C, Iamsaard S. Toxicity evaluation of Dolichandrone serrulata flower extract on vital and reproductive organs in adult male rats. BRAZ J BIOL 2021; 84:e251224. [PMID: 34932676 DOI: 10.1590/1519-6984.251224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 07/25/2021] [Indexed: 11/21/2022] Open
Abstract
Although Dolichandrone serrulata flower (DSF) aqueous extract has been shown to possess pharmacological properties, its systemic toxicity has still to be evaluated. The present study aimed to investigate the sub-chronic toxicity effect of DSF extract on biochemical parameters and histological structures of liver, kidney, testis, and epididymis plus vas deferens. Adult male rats were administered DSF at 100, 300, and 600 mg/kgBW via oral gavage for 48 consecutive days while control rats received distilled water. At the end of the experiment, blood, liver, kidney, testis, and epididymis plus vas deferens samples were collected to determine any changes to serum biochemical components including ALT, ALP, and creatinine levels and histological structures. The results revealed no significant difference in body weight and food or water consumption between control and the DSF-treated groups. It was found that DSF significantly increases the weight of epididymis plus vas deferens, while the kidney and liver showed a decrease in the high dose group (P value < 0.05). Histological changes in these vital and reproductive tissues including fibrosis were not observed after administration but ALT, ALP, and creatinine levels were significantly altered in the treated groups (P value < 0.05). These altered levels, however, were still within normal ranges. In conclusion, these findings demonstrated that D. serrulata flower extract had no sub-chronic toxicity on vital and reproductive structures but slightly altered some liver and kidney functions.
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Affiliation(s)
- C Chaimontri
- Khon Kaen University, Faculty of Medicine, Department of Anatomy, Khon Kaen, Thailand
| | - S Iamsaard
- Khon Kaen University, Faculty of Medicine, Department of Anatomy, Khon Kaen, Thailand.,Khon Kaen University, Research Institute for Human High Performance and Health Promotion, Khon Kaen, Thailand
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Vazquez-Padron RI, Duque JC, Tabbara M, Salman LH, Martinez L. Intimal Hyperplasia and Arteriovenous Fistula Failure: Looking Beyond Size Differences. KIDNEY360 2021; 2:1360-1372. [PMID: 34765989 PMCID: PMC8579754 DOI: 10.34067/kid.0002022021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The development of venous intimal hyperplasia (IH) has been historically associated with failure of arteriovenous fistulas (AVF) used for hemodialysis. This long-standing assumption, based on histological observations, has been recently challenged by clinical studies indicating that the size of the intima by itself is not enough to explain stenosis or AVF maturation failure. Irrespective of this lack of association, IH is present in most native veins and fistulas, is prominent in many cases, and suggests a role in the vein that may not be reflected by its dimensions. Therefore, the contribution of IH to AVF dysfunction remains controversial. Using only clinical data and avoiding extrapolations from animal models, we critically discuss the biological significance of IH in vein remodeling, vascular access function, and the response of the venous wall to repeated trauma in hemodialysis patients. We address questions and pose new ones such as: What are the factors that contribute to IH in pre-access veins and AVFs? Do cellular phenotypes and composition of the intima influence AVF function? Are there protective roles of the venous intima? This review explores these possibilities, with hopes of rekindling a critical discussion about venous IH that goes beyond thickness and AVF outcomes.
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Affiliation(s)
- Roberto I Vazquez-Padron
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida
| | - Juan C Duque
- Katz Family Division of Nephrology, Department of Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida
| | - Marwan Tabbara
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida
| | - Loay H Salman
- Division of Nephrology, Albany Medical College, Albany, New York
| | - Laisel Martinez
- DeWitt Daughtry Family Department of Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida
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Eekhoff JD, Lake SP. Three-dimensional computation of fibre orientation, diameter and branching in segmented image stacks of fibrous networks. J R Soc Interface 2020; 17:20200371. [PMID: 32752994 PMCID: PMC7482563 DOI: 10.1098/rsif.2020.0371] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/15/2020] [Indexed: 12/27/2022] Open
Abstract
Fibre topography of the extracellular matrix governs local mechanical properties and cellular behaviour including migration and gene expression. While quantifying properties of the fibrous network provides valuable data that could be used across a breadth of biomedical disciplines, most available techniques are limited to two dimensions and, therefore, do not fully capture the architecture of three-dimensional (3D) tissue. The currently available 3D techniques have limited accuracy and applicability and many are restricted to a specific imaging modality. To address this need, we developed a novel fibre analysis algorithm capable of determining fibre orientation, fibre diameter and fibre branching on a voxel-wise basis in image stacks with distinct fibre populations. The accuracy of the technique is demonstrated on computer-generated phantom image stacks spanning a range of features and complexities, as well as on two-photon microscopy image stacks of elastic fibres in bovine tendon and dermis. Additionally, we propose a measure of axial spherical variance which can be used to define the degree of fibre alignment in a distribution of 3D orientations. This method provides a useful tool to quantify orientation distributions and variance on image stacks with distinguishable fibres or fibre-like structures.
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Affiliation(s)
- Jeremy D. Eekhoff
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO 63110, USA
| | - Spencer P. Lake
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO 63110, USA
- Department of Mechanical Engineering and Materials Science, Washington University in St Louis, St Louis, MO 63110, USA
- Department of Orthopaedic Surgery, Washington University in St Louis, St Louis, MO 63110, USA
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