PMID- 35660943
OWN - NLM
STAT- MEDLINE
DCOM- 20220627
LR  - 20240216
IS  - 1872-7565 (Electronic)
IS  - 0169-2607 (Print)
IS  - 0169-2607 (Linking)
VI  - 221
DP  - 2022 Jun
TI  - Biomechanics of human trabecular meshwork in healthy and glaucoma eyes via 
      dynamic Schlemm's canal pressurization.
PG  - 106921
LID - S0169-2607(22)00303-0 [pii]
LID - 10.1016/j.cmpb.2022.106921 [doi]
AB  - BACKGROUND AND OBJECTIVE: The trabecular meshwork (TM) consists of extracellular 
      matrix (ECM) with embedded collagen and elastin fibers providing its mechanical 
      support. TM stiffness is considerably higher in glaucoma eyes. Emerging data 
      indicates that the TM moves dynamically with transient intraocular pressure (IOP) 
      fluctuations, implying the viscoelastic mechanical behavior of the TM. However, 
      little is known about TM viscoelastic behavior. We calculated the viscoelastic 
      mechanical properties of the TM in n = 2 healthy and n = 2 glaucoma eyes. 
      METHODS: A quadrant of the anterior segment was submerged in a saline bath, and a 
      cannula connected to an adjustable saline reservoir was inserted into Schlemm's 
      canal (SC). A spectral domain-OCT (SD-OCT) provided continuous cross-sectional 
      B-scans of the TM/JCT/SC complex during pressure oscillation from 0 to 30 mmHg at 
      two locations. The TM/JCT/SC complex boundaries were delineated to construct a 
      20-microm-thick volume finite element (FE) mesh. Pre-tensioned collagen and elastin 
      fibrils were embedded in the model using a mesh-free penalty-based cable-in-solid 
      algorithm. SC pressure was represented by a position- and time-dependent pressure 
      boundary; floating boundary conditions were applied to the other cut edges of the 
      model. An FE-optimization algorithm was used to adjust the ECM/fiber mechanical 
      properties such that the TM/JCT/SC model and SD-OCT imaging data best matched 
      over time. RESULTS: Significantly larger short- and long-time ECM shear moduli 
      (p = 0.0032), and collagen (1.82x) and elastin (2.72x) fibril elastic moduli 
      (p = 0.0001), were found in the TM of glaucoma eyes compared to healthy controls. 
      CONCLUSIONS: These findings provide additional clarity on the mechanical property 
      differences in healthy and glaucomatous outflow pathway under dynamic loading. 
      Understanding the viscoelastic properties of the TM may serve as a new biomarker 
      in early diagnosis of glaucoma.
CI  - Copyright (c) 2022 Elsevier B.V. All rights reserved.
FAU - Karimi, Alireza
AU  - Karimi A
AD  - Department of Ophthalmology and Visual Sciences, University of Alabama at 
      Birmingham, Birmingham, AL, USA. Electronic address: akarimi@uabmc.edu.
FAU - Rahmati, Seyed Mohammadali
AU  - Rahmati SM
AD  - School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA. 
      Electronic address: srahmati3@gatech.edu.
FAU - Razaghi, Reza
AU  - Razaghi R
AD  - Department of Ophthalmology and Visual Sciences, University of Alabama at 
      Birmingham, Birmingham, AL, USA.
FAU - Crawford Downs, J
AU  - Crawford Downs J
AD  - Department of Ophthalmology and Visual Sciences, University of Alabama at 
      Birmingham, Birmingham, AL, USA. Electronic address: cdowns@uabmc.edu.
FAU - Acott, Ted S
AU  - Acott TS
AD  - Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon 
      Health & Science University, Portland, Oregon, USA. Electronic address: 
      acott@ohsu.edu.
FAU - Wang, Ruikang K
AU  - Wang RK
AD  - Department of Ophthalmology, University of Washington, Seattle, WA, USA; 
      Department of Bioengineering, University of Washington, Seattle, WA, USA. 
      Electronic address: wangrk@u.washington.edu.
FAU - Johnstone, Murray
AU  - Johnstone M
AD  - Department of Ophthalmology, University of Washington, Seattle, WA, USA. 
      Electronic address: murrayj2@uw.edu.
LA  - eng
GR  - R01 EY028753/EY/NEI NIH HHS/United States
GR  - P30 EY010572/EY/NEI NIH HHS/United States
GR  - R01 EY030238/EY/NEI NIH HHS/United States
GR  - R01 EY024158/EY/NEI NIH HHS/United States
GR  - R01 EY018926/EY/NEI NIH HHS/United States
GR  - R01 EY025721/EY/NEI NIH HHS/United States
GR  - P30 EY003039/EY/NEI NIH HHS/United States
GR  - R01 EY027924/EY/NEI NIH HHS/United States
PT  - Journal Article
DEP - 20220527
PL  - Ireland
TA  - Comput Methods Programs Biomed
JT  - Computer methods and programs in biomedicine
JID - 8506513
RN  - 9007-58-3 (Elastin)
SB  - IM
MH  - Biomechanical Phenomena
MH  - Cross-Sectional Studies
MH  - Elastin/metabolism
MH  - *Glaucoma/diagnostic imaging
MH  - Humans
MH  - *Trabecular Meshwork/metabolism
PMC - PMC10424782
MID - NIHMS1919084
OTO - NOTNLM
OT  - Collagen and elastin fibers
OT  - Finite element-optimization
OT  - Glaucoma
OT  - Ocular biomechanics
OT  - Trabecular meshwork
COIS- Declaration of Competing Interest The authors declare that they have no known 
      competing financial interests or personal relationships that could have appeared 
      to influence the work reported in this paper.
EDAT- 2022/06/07 06:00
MHDA- 2022/06/28 06:00
PMCR- 2023/08/14
CRDT- 2022/06/06 12:00
PHST- 2022/03/03 00:00 [received]
PHST- 2022/05/17 00:00 [revised]
PHST- 2022/05/26 00:00 [accepted]
PHST- 2022/06/07 06:00 [pubmed]
PHST- 2022/06/28 06:00 [medline]
PHST- 2022/06/06 12:00 [entrez]
PHST- 2023/08/14 00:00 [pmc-release]
AID - S0169-2607(22)00303-0 [pii]
AID - 10.1016/j.cmpb.2022.106921 [doi]
PST - ppublish
SO  - Comput Methods Programs Biomed. 2022 Jun;221:106921. doi: 
      10.1016/j.cmpb.2022.106921. Epub 2022 May 27.