Differential Vitreous Dye Diffusion Following Microplasmin or Plasmin Pre-Treatment

Elkareem, Ashraf M. Gad; Willikens, Ben; Stassen, Jean Marie; Smet, Marc D. de

doi:10.3109/02713680903484259

Cited by 12 publications

(13 citation statements)

References 28 publications

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“…In an elegant study, Goldenberg et al 15 demonstrated that bevacizumab was absorbed more quickly through the retina following microplasmin-induced posterior vitreous detachment compared with nontreated eyes in a rabbit model. Gad Elkareem et al 16 demonstrated higher differential fluorescein diffusion rates in both plasmin and microplasmin compared with saline-treated vitreous cavities.…”

Section: Discussionmentioning

confidence: 99%

Anatomic and Pharmacokinetic Properties of Intravitreal Bevacizumab and Ranibizumab After Vitrectomy and Lensectomy

Christoforidis

Williams²,

Wang³

et al. 2013

Retina

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Purpose To determine the anatomic characteristics and pharmacokinetic properties of intravitreally placed bevacizumab and ranibizumab after pars plana lensectomy or pars plana vitrectomy and to compare these with nonoperated control eyes in a rabbit model. Methods Three groups of six Dutch-belted rabbits each underwent pars plana vitrectomy, pars plana lensectomy, or served as nonsurgical controls. Twelve days after surgery, 3 rabbits from each group underwent intravitreal injection in one eye with 1.25 mg/0.05 mL I-124–bevacizumab or 0.5 mg/0.05 mL I-124-ranibizumab. Serial imaging with PET/CT were obtained on Days 0, 2, 5, 7, 14, 21, 28, and 35. Measured radioactivity emission in becquerels/milliliter was used to calculate the half-lives for each agent. Results The intravitreally placed radiolabeled agents were contained within the vitreous cavity for the duration of the study. The average clearance half-lives with standard error for bevacizumab and ranibizumab after correction for radioactive decay were, respectively, 4.22 ± 0.07 days and 2.81 ± 0.05 days in unoperated eyes, 2.30 ± 0.09 days (P < 0.0001) and 2.13 ± 0.05 days (P < 0.0001) after vitrectomy, and 2.08 ± 0.07 days (P = 0.0001) and 1.79 ± 0.05 days (P < 0.0001) after lensectomy. Conclusion Intravitreal retention was longer for bevacizumab than ranibizumab within all study groups and was significantly reduced after vitrectomy and lensectomy for both agents. Consideration for more frequent intravitreal anti–vascular endothelial growth factor dosing regimens may be made for patients whose treated eyes have undergone previous vitrectomy or who are aphakic.

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Section: Discussionmentioning

confidence: 99%

Anatomic and Pharmacokinetic Properties of Intravitreal Bevacizumab and Ranibizumab After Vitrectomy and Lensectomy

Christoforidis

Williams²,

Wang³

et al. 2013

Retina

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“…[15][16][17] Assessment of dispersion was done by ophthalmoscopy or by dissecting the vitreous carefully out of the eye. In this study, a new method was established using an UHRCT scanner and a radio-opaque contrast agent to visualize the dispersion in a 3D-reconstructed manner without any vitreous manipulation.…”

Section: Discussionmentioning

confidence: 99%

“…This has previously been studied either by using Indian ink or fluorescein. [15][16][17] Both colorants are easily visualized in the vitreous cavity, but it is difficult to assess or measure the real size, shape, and dispersion rate of the contrast bubble by ophthalmoscopy. Furthermore, follow-up over a period of hours or days requires in vivo tests because the cornea and lens will hinder visualization in enucleated eyes.…”

mentioning

confidence: 99%

Intravitreally Injected Fluid Dispersion: Importance of Injection Technique

Willekens

Reyns²,

Diricx³

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. The purpose of this study was to evaluate the dispersion of intravitreally injected solutions and investigate the influence of varying injection techniques.METHODS. This was a prospective study using enucleated porcine eyes and ultra-highresolution computed tomography (UHRCT) scanning to visualize iomeprol intravitreal dispersion. Sixty eyes were divided over 12 different groups according to the injection procedure: fast (2 seconds) or slow (10 seconds) injection speed and needle tip location (6-and 12-mm needle shaft insertion or premacular tip placement verified by indirect ophthalmoscopy). For each of these combinations, eyes were either injected with the combination of V20I (which is an analogue of ocriplasmin) and iomeprol or iomeprol alone. Distance to the macula and volume measurements were performed at 1, 2, 3, and 5 hours after injection.RESULTS. The measured contrast bolus volume increases slowly over time to an average of 0.70 (P ¼ 0.03), 1.04 (P ¼ 0.006), and 0.79 (P ¼ 0.0001) cm 3 5 hours after the injection for the 6-mm needle shaft insertion, 12-mm needle shaft insertion, and premacular needle tip placement, respectively. The distance to the macular marker was significantly lower for premacular needle tip placement injections compared with 6-and 12-mm needle shaft insertion depths.CONCLUSIONS. Ultra-high-resolution computed tomography with three-dimensional reconstruction offers the possibility to study the dispersion of intravitreally injected solutions in a noninvasive manner. Intravitreal premacular solution delivery is possible with an indirect ophthalmoscope-guided injection technique and significantly reduces the time to reach the posterior pole in respect to 6-and 12-mm needle insertion depths. The speed of injection does not influence dispersion significantly.

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“…9 Ocriplasmin's activity is pH dependent; at a neutral pH, it has a high lytic activity. It hydrolyzes collagen, laminin, and fibronectin.…”

Section: ' Preclinical Studies Of Ocriplasminmentioning

confidence: 99%

Ocriplasmin and its Role in the Management of Vitreoretinal Interface Disorders

Weng¹,

Fortun²,

Carvounis³

et al. 2014

International Ophthalmology Clinics

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The vitreous gel has an outer cortex consisting primarily of type II collagen that is attached to the internal limiting membrane (ILM) consisting primarily of type IV collagen. The vitreous plays a central role in many common and potentially blinding diseases such as diabetic retinopathy, proliferative vitreoretinopathy, and vitreomacular interface disorders; the latter will be the focus here.The development of a posterior vitreous detachment is a natural process that occurs typically after the age of 50 years. However, sometimes the posterior hyaloid face does not detach completely and there are focal areas that remain attached to the macula. This is a condition known as vitreomacular adhesion (VMA). In a recent noncomparative case series of 106 eyes with symptomatic idiopathic VMA, spontaneous release of VMA occurred in 34% of eyes during the mean study follow-up period of 23 months. 1 In the cases where VMA does not resolve on its own, traction on the retina may develop, leading to subsequent anatomic distortion; although the terminology is not universally accepted, this anatomic distortion on OCT in the setting of VMA is referred to as vitreomacular traction (VMT).If left untreated, VMT can sometimes progress into a sight-threatening condition where patients can experience decreased visual acuity, metamorphopsia, and scotomas; full-thickness macular holes can also form as a result of VMT. In a retrospective analysis of 53 consecutive symptomatic eyes with untreated VMT, Hikichi et al 2 found that 64% of eyes experienced a decrease in visual acuity of Z2 Snellen lines after a

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Differential Vitreous Dye Diffusion Following Microplasmin or Plasmin Pre-Treatment

Abstract: Microplasmin and plasmin have a similar enzymatic effect on vitreous. However, an equipotent amount of microplasmin appears to have a more extended effect on vitreous gel. This may, in part, be related to its smaller size allowing it to diffuse more readily through the vitreous matrix.

Cited by 12 publications

References 28 publications

Anatomic and Pharmacokinetic Properties of Intravitreal Bevacizumab and Ranibizumab After Vitrectomy and Lensectomy

Anatomic and Pharmacokinetic Properties of Intravitreal Bevacizumab and Ranibizumab After Vitrectomy and Lensectomy

Intravitreally Injected Fluid Dispersion: Importance of Injection Technique

Ocriplasmin and its Role in the Management of Vitreoretinal Interface Disorders

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