scholarly journals A Surgical Cryoprobe for Targeted Transcorneal Freezing and Endothelial Cell Removal

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Alina Akhbanbetova ◽  
Shinichiro Nakano ◽  
Stacy L. Littlechild ◽  
Robert D. Young ◽  
Madara Zvirgzdina ◽  
...  

Purpose. To examine the effects of transcorneal freezing using a new cryoprobe designed for corneal endothelial surgery. Methods. A freezing console employing nitrous oxide as a cryogen was used to cool a series of different cryoprobe tip designs made of silver for high thermal conductivity. In vitro studies were conducted on 426 porcine corneas, followed by preliminary in vivo investigations on three rabbit corneas. Results. The corneal epithelium was destroyed by transcorneal freezing, as expected; however, the epithelial basement membrane remained intact. Reproducible endothelial damage was optimally achieved using a 3.4 mm diameter cryoprobe with a concave tip profile. Stromal edema was seen in the pre-Descemet’s area 24 hrs postfreeze injury, but this had been resolved by 10 days postfreeze. A normal collagen fibril structure was seen 1 month postfreeze, concurrent with endothelial cell repopulation. Conclusions. Transcorneal freezing induces transient posterior stromal edema and some residual deep stromal haze but leaves the epithelial basement membrane intact, which is likely to be important for corneal re-epithelialization. Localized destruction of the endothelial monolayer was achieved in a consistent manner with a 3.4 mm diameter/concave profile cryoprobe and represents a potentially useful approach to remove dysfunctional corneal endothelial cells from corneas with endothelial dysfunction.

1990 ◽  
Vol 27 (1) ◽  
pp. 14-23
Author(s):  
Shinobu Matsuo ◽  
Neal S. Penneys ◽  
Jo-David Fine ◽  
Steffen Gay ◽  
Mehrdad Nadji

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3206-3217 ◽  
Author(s):  
N Dubois-Stringfellow ◽  
A Jonczyk ◽  
VL Bautch

Abstract Fibrinolytic activity and its relation to morphogenesis was investigated in several transformed murine endothelial cell lines and primary cultures of endothelial cells. Two in vitro systems, fibrin gels and Matrigel (Collaborative Research, Bedford, MA), were used. Fibrin gels model a fibrin-rich extracellular matrix that frequently supports neovascularization in vivo, and Matrigel models the basement membrane surrounding quiescent endothelial cells in vivo. The transformed endothelial cell lines have higher levels of plasminogen activator (PA) mRNA than primary cultures of endothelial cells, and an increased PA-mediated proteolytic activity was correlated with formation of cysts in fibrin gels. Addition of neutralizing anti- urokinase antibodies, plasminogen depletion, or addition of a plasmin inhibitor prevented cyst formation. Addition of plasminogen restored the ability to form cysts in the plasminogen-depleted system. Normal endothelial cells organized into capillary-like structures in fibrin gels regardless of manipulations affecting the fibrinolytic pathway. In Matrigel, both transformed and primary cultures of endothelial cells rapidly formed a capillary-like network that was not affected by plasminogen depletion or addition of plasmin inhibitors. Thus, elements of the fibrinolytic pathway necessary for cyst formation are not critical in capillary-like structure formation on a reconstituted basement membrane. These results suggest that plasmin is essential for hemangioma formation but is not critical to the organizational behavior of normal endothelial cells.


1996 ◽  
Vol 132 (6) ◽  
pp. 1189-1198 ◽  
Author(s):  
M F Champliaud ◽  
G P Lunstrum ◽  
P Rousselle ◽  
T Nishiyama ◽  
D R Keene ◽  
...  

Stable attachment of external epithelia to the basement membrane and underlying stroma is mediated by transmembrane proteins such as the integrin alpha6beta4 and bullous pemphigoid antigen 2 within the hemidesmosomes along the basolateral surface of the epithelial cell and their ligands that include a specialized subfamily of laminins. The laminin 5 molecule (previously termed kalinin/nicein/epiligrin) is a member of this epithelial-specific subfamily. Laminin 5 chains are not only considerably truncated within domains III-VI, but are also extensively proteolytically processed in vitro and in vivo. As a result, the domains expected to be required for the association of laminins with other basement membrane components are lacking in the mature laminin 5 molecule. Therefore, the tight binding of laminin 5 to the basement membrane may occur by a unique mechanism. To examine laminin 5 in tissue, we chose human amnion as the source, because of its availability and the similarity of the amniotic epithelial basement membrane with that of skin. We isolated the laminin 5 contained within the basement membrane of human amnion. In addition to monomeric laminin 5, we find that much of the laminin 5 isolated is covalently adducted with laminin 6 (alpha3beta1gamma1) and a novel laminin isotype we have termed laminin 7 (alpha3beta2gamma1). We propose that the association between laminin 5 and laminins 6 and 7 is a mechanism used in amnion to allow stable association of laminin 5 with the basement membrane. The beta2 chain is seen at the human amniotic epithelial-stromal interface and at the dermal-epidermal junction of fetal and adult bovine skin by immunofluorescence, but is not present, or only weakly present, in neonatal human skin.


2009 ◽  
Vol 77 (8) ◽  
pp. 3264-3271 ◽  
Author(s):  
Irania Alarcon ◽  
Lesley Kwan ◽  
Chong Yu ◽  
David J. Evans ◽  
Suzanne M. J. Fleiszig

ABSTRACT Pseudomonas aeruginosa can invade corneal epithelial cells and translocates multilayered corneal epithelia in vitro, but it does not penetrate the intact corneal epithelium in vivo. In healthy corneas, the epithelium is separated from the underlying stroma by a basement membrane containing extracellular matrix proteins and pores smaller than bacteria. Here we used in vivo and in vitro models to investigate the potential of the basement membrane to defend against P. aeruginosa. Transmission electron microscopy of infected mouse corneas in vivo showed penetration of the stroma by P. aeruginosa only where the basement membrane was visibly disrupted by scratch injury, suggesting that the intact basement membrane prevented penetration. This hypothesis was explored using an in vitro Matrigel Transwell model to mimic the corneal basement membrane. P. aeruginosa translocation of multilayered corneal epithelia grown on Matrigel was ∼100-fold lower than that of cells grown without Matrigel (P < 0.005, t test). Matrigel did not increase transepithelial resistance. Matrigel-grown cells blocked translocation by a P. aeruginosa protease mutant. Without cells, Matrigel also reduced traversal of P. aeruginosa and the protease mutant. Fluorescence microscopy revealed a relative accumulation of bacteria at the superficial epithelium of cells grown on Matrigel at 3 h compared to cells grown on uncoated filters. By 5 h, bacteria accumulated beneath the cells, suggesting direct trapping by the Matrigel. These findings suggest that the basement membrane helps defend the cornea against infection via physical barrier effects and influences on the epithelium and that these roles could be compromised by P. aeruginosa proteases.


Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3206-3217 ◽  
Author(s):  
N Dubois-Stringfellow ◽  
A Jonczyk ◽  
VL Bautch

Fibrinolytic activity and its relation to morphogenesis was investigated in several transformed murine endothelial cell lines and primary cultures of endothelial cells. Two in vitro systems, fibrin gels and Matrigel (Collaborative Research, Bedford, MA), were used. Fibrin gels model a fibrin-rich extracellular matrix that frequently supports neovascularization in vivo, and Matrigel models the basement membrane surrounding quiescent endothelial cells in vivo. The transformed endothelial cell lines have higher levels of plasminogen activator (PA) mRNA than primary cultures of endothelial cells, and an increased PA-mediated proteolytic activity was correlated with formation of cysts in fibrin gels. Addition of neutralizing anti- urokinase antibodies, plasminogen depletion, or addition of a plasmin inhibitor prevented cyst formation. Addition of plasminogen restored the ability to form cysts in the plasminogen-depleted system. Normal endothelial cells organized into capillary-like structures in fibrin gels regardless of manipulations affecting the fibrinolytic pathway. In Matrigel, both transformed and primary cultures of endothelial cells rapidly formed a capillary-like network that was not affected by plasminogen depletion or addition of plasmin inhibitors. Thus, elements of the fibrinolytic pathway necessary for cyst formation are not critical in capillary-like structure formation on a reconstituted basement membrane. These results suggest that plasmin is essential for hemangioma formation but is not critical to the organizational behavior of normal endothelial cells.


Sign in / Sign up

Export Citation Format

Share Document