Evaluation of the IOP-Lowering Effect of a Multi-Pressure Dial at Different Negative Pressure Settings

Purpose

To evaluate the intraocular pressure (IOP)-lowering effect of a multi-pressure dial (MPD) at targeted negative pressure settings.

Methods

Prospective, intrasubject controlled study of 65 healthy subjects randomized to receive no negative pressure for 60 minutes or negative pressure application at designated levels of 25%, 50%, and 75% of baseline IOP for 20 minutes each. The main outcome measure was mean IOP with application of negative pressure.

Results

In the study eye group, from a baseline IOP of 15.8 ± 3.6 mm Hg, the mean IOP was 13.5 ± 3.4, 11.5 ± 3.1, and 10.2 ± 2.7 mm Hg with negative pressure settings of 25%, 50% and 75%, respectively. In the control eye group, from a baseline IOP of 15.5 ± 3.0 mm Hg, the mean IOP values at the same time points, without negative pressure, were 15.6 ± 3.0, 15.5 ± 2.5 and 15.3 ± 2.4 mm Hg. The difference between the mean IOPs of the two groups was significantly different at all negative pressure settings (P < 0.001) in comparison with baseline. There was one minor adverse event, a corneal abrasion, that was unrelated to device wear.

Conclusions

Negative pressure application to the periocular space with a multi-pressure dial can produce titratable IOP reduction while the device is worn with active negative pressure. To our knowledge, this technology represents the first nonpharmacologic, nonlaser, nonsurgical method for IOP reduction.

Translational Relevance

This represents the first study demonstrating the IOP-lowering ability of the multi-pressure dial, a device that uses a novel IOP-lowering strategy by delivering negative pressure to the periocular region.

Intraocular Pressure Measurement with Pneumatonometry and a Tonometer Tip Cover

Purpose

To investigate the precision and accuracy of IOP measurements using a pneumatonometer and a tonometer tip cover (Tono-Pen^® tip cover) acting as a membrane between a cadaver eye model and pneumatonometer probe.

Methods

A total of 480 paired IOP measurements, with and without a Tono-Pen cover, were collected across 4 pressure levels of 7, 10, 20 and 30 mmHg. IOP measurements were obtained by three different pneumatonometer units paired with three different masked operators (three configurations). Four eyes were sampled for each eye pressure level. The sequence of eye pressure, configuration, and measurements with vs. without the Tono-Pen cover was randomized.

Results

With the Tono-Pen cover in place, there was a negative bias with a mean IOP difference of − 1.18 mmHg for all 480 paired samples compared with the measurements absent the cover. Compared with the test pressure settings (i.e., 7, 10, 20, 30 mmHg), the overall mean bias was + 0.35 mmHg with the Tono-Pen cover present. With the Tono-Pen cover present, the overall repeatability %CV (percent coefficient of variation) was 3.4% and the reproducibility %CV was 3.8% compared with a repeatability %CV of 3.2% and reproducibility %CV of 5.7% without the Tono-Pen cover.

Conclusion

Measurement of IOP via pneumatonometry with a Tono-Pen cover in place, also known as the excursion test method, yields precise, accurate and reproducible results. This developed method of pressure measurement is an acceptable and reliable form of IOP measurement.

Comparing consistency of clear corneal incisions using a traditional diamond keratome and a newly designed diamond keratome

Purpose

To compare the consistency of incision architecture utilizing a traditional diamond keratome and a newly designed diamond keratome.

Methods

We used a traditional diamond keratome and newly designed diamond keratome to create clear corneal incisions in human cadaveric donor eyes. Three surgeons with varying levels of experience made 30 incisions with each keratome; and the wound architecture was measured including incision lengths, epithelial and endothelial widths, and the central epithelial incision’s deviation from a straight line entrance.

Results

The mean absolute difference in right and left incision lengths (traditional: 0.182 ± 0.158 mm and new 0.088±0.077 mm [P<0.003]), mean absolute difference in epithelial and endothelial incision width (traditional: 0.181±0.144 mm and new 0.080±0.092 mm [P<0.002]), endothelial incision central deviation from a straight line (traditional: 0.128±0.242 mm and new −0.046±0.124 mm [P<0.001]) were all significantly more consistent with the newly designed diamond keratome than with the traditional diamond keratome.

Conclusion

The newly designed diamond keratome creates a more consistent clear corneal incision than a traditional diamond keratome across a variety of surgical skill levels and does not require advanced levels of training to achieve this consistency.

AAV serotype 2/1-mediated gene delivery of anti-inflammatory interleukin-10 enhances neurogenesis and cognitive function in APP+PS1 mice

Brain inflammation is a double-edged sword: it is required for brain repair in acute damage, whereas chronic inflammation and autoimmune disorders are neuropathogenic. Certain pro-inflammatory cytokines and chemokines are closely related to cognitive dysfunction and neurodegeneration. Representative anti-inflammatory cytokines, such as interleukin (IL)-10, can suppress neuroinflammation and have significant therapeutic potentials in ameliorating neurodegenerative disorders, such as Alzheimer’s disease (AD). Here, we show that adeno-associated virus (AAV) serotype 2/1 hybrid-mediated neuronal expression of the mouse IL-10 gene ameliorates cognitive dysfunction in APP+PS1 bigenic mice. AAV2/1 infection of hippocampal neurons resulted in sustained expression of IL-10 without its leakage into the blood, reduced astro/microgliosis, enhanced plasma amyloid-β peptide (Aβ) levels, and enhanced neurogenesis. Moreover, increased levels of IL-10 improved spatial learning as determined by the radial arm water maze. Finally, IL-10-stimulated microglia enhanced proliferation but not differentiation of primary neural stem cells in the co-culture system, while IL-10 itself had no effect. Our data suggest that IL-10 gene delivery has a therapeutic potential for a non-Aβ-targeted treatment of AD.

CNS expression of anti-inflammatory cytokine interleukin-4 attenuates Alzheimer's disease-like pathogenesis in APP+PS1 bigenic mice

Cytokines play an emerging role as neurotransmitters, neuromodulators, and neurohormones in the brain. This paradigm shift in cytokine function offers a new framework to understand their roles in ameliorating neurodegenerative disorders, such as Alzheimer's disease (AD). Molecular adjuvant therapy of AD animal models with glatiramer acetate induces anti-inflammatory responses and therapeutic effects. Although these effects are potentially mediated through anti-inflammatory cytokine signaling, the exact molecular identities and pathways are poorly understood. Here, we show that virus-mediated expression of the mouse interleukin (IL)-4 gene in beta-amyloid precursor protein + presenilin-1 (APP+PS1) bigenic mice attenuates AD pathogenesis. Introduction of an adeno-associated viral (AAV) vector encoding IL-4 into the hippocampus resulted in sustained expression of IL-4, reduced astro/microgliosis, amyloid-beta peptide (Abeta) oligomerization and deposition, and enhanced neurogenesis. Moreover, increased levels of IL-4 improved spatial learning, promoted phosphorylation of N-methyl-D-aspartate receptor subunit 2B at Tyr 1472, and enhanced its cell surface retention both in vivo and in vitro. Our data suggest that neuronal anti-inflammatory cytokine signaling may be a potential alternative target for non-Abeta-mediated treatment of AD.

AAV1/2-mediated CNS gene delivery of dominant-negative CCL2 mutant suppresses gliosis, beta-amyloidosis, and learning impairment of APP/PS1 mice

Accumulation of aggregated amyloid-beta (Abeta) peptide was studied as an initial step for Alzheimer's disease (AD) pathogenesis. Following amyloid plaque formation, reactive microglia and astrocytes accumulate around plaques and cause neuroinflammation. Here brain chemokines play a major role for the glial accumulation. We have previously shown that transgenic overexpression of chemokine CCL2 in the brain results in increased microglial accumulation and diffuse amyloid plaque deposition in a transgenic mouse model of AD expressing Swedish amyloid precursor protein (APP) mutant. Here, we report that adeno-associated virus (AAV) serotype 1 and 2 hybrid efficiently deliver 7ND gene, a dominant-negative CCL2 mutant, in a dose-response manner and express >1,000-fold higher recombinant CCL2 than basal levels after a single administration. AAV1/2 hybrid virus principally infected neurons without neuroinflammation with sustained expression for 6-months. 7ND expressed in APP/presenilin-1 (APP/PS1) bigenic mice reduced astro/microgliosis, beta-amyloidosis, including suppression of both fibrillar and oligomer Abeta accumulation, and improved spatial learning. Our data support the idea that the AAV1/2 system is a useful tool for CNS gene delivery, and suppression of CCL2 may be a therapeutic target for the amelioration of AD-related neuroinflammation.

Properties of optical data from activated partial thromboplastin time and prothrombin time assays

Changes in characteristics of optical transmittance data from coagulation assays were examined as a function of concentration of coagulation proteins or anticoagulants. Transmittance data were collected for activated partial thromboplastin time (APTT) and prothrombin time (PT) assays from: 1) plasmas prepared by mixing normal plasmas with deficient plasmas to give varying levels of coagulation proteins; 2) plasmas containing added heparin; and 3) 200 specimen plasmas that were also assayed for fibrinogen, coagulation factors, and other components. Optical profiles were characterized using a set of parameters describing onset and completion of coagulation, magnitude of signal change, rate of coagulation and other properties. Results indicated that parameters other than those typically reported for APTT and PT are associated with individual deficiencies, but that diagnosis of specimen status on the basis of optical data is complex. These results suggest possibilities for expanded interpretation of PT/APTT optical data for clinical or research applications.