Relationship between corneal sensitivity, corneal thickness, corneal diameter, and intraocular pressure in normal cats and cats with congenital glaucoma.

OBJECTIVE: To determine the effect of feline congenital glaucoma (FCG) on corneal sensitivity, and relationships between corneal sensitivity, central corneal thickness (CT), and corneal diameter (CD). ANIMALS AND PROCEDURES: Corneal sensitivity (estimated by corneal touch threshold [CTT] using Cochet-Bonnet esthesiometry); CT using ultrasonic pachymetry; intraocular pressure (IOP) using rebound tonometry; and maximal horizontal CD were measured in 16 normal and 14 FCG cats, both males and females, aged 7 months-3.5 years. All procedures complied with an Institutional Animal Care and Use Committee-approved protocol. Data were analyzed by linear regression: paired Student's t tests for between-eye comparisons, and unpaired Student's t tests for comparisons between groups. Relationships between parameters were evaluated by Pearson correlation coefficients and linear mixed effects modeling. For statistical tests, with the exception of values that were Benjamini-Hochberg adjusted for multiple comparisons, P-values < 0.05 were considered significant. RESULTS: Mean CTT and CT values were lower in FCG eyes relative to normal eyes, but differences were not statistically significant. Mean CD was significantly larger in FCG eyes relative to normal eyes, and there was a significant negative correlation between CD and CTT in FCG (r = -0.8564, corrected P = 0.005). These associations were confirmed in linear mixed effects models. CONCLUSIONS: Eyes with FCG have significantly larger CDs when compared with normal eyes, and larger CDs correlated with decreased corneal sensitivity in this group. Further studies are warranted to explore the effect of buphthalmos and corneal enlargement on corneal sensitivity and innervation in feline subjects with chronic glaucoma.

Meta-analysis of transcriptomic changes in optic nerve injury and neurodegenerative models reveals a fundamental response to injury throughout the central nervous system.

Purpose: Injury to the central nervous system (CNS) leads to transcriptional changes that effect tissue function and govern the process of neurodegeneration. Numerous microarray and RNA-Seq studies have been performed to identify these transcriptional changes in the retina following optic nerve injury and elsewhere in the CNS following a variety of insults. We reasoned that conserved transcriptional changes between injury paradigms would be important contributors to the neurodegenerative process. Therefore, we compared the expression results from heterogeneous studies of optic nerve injury and neurodegenerative models. Methods: Expression data was collected from the Gene Expression Omnibus. A uniform method for normalizing expression data and detecting differentially expressed (DE) genes was used to compare the transcriptomes from models of acute optic nerve injury (AONI), chronic optic nerve injury (CONI) and brain neurodegeneration. DE genes were split into genes that were more or less prevalent in the injured condition than the control condition (enriched and depleted, respectively) and transformed into their human orthologs so that transcriptomes from different species could be compared. Biologic significance of shared genes was assessed by analyzing lists of shared genes for gene ontology (GO) term over-representation and for representation in KEGG pathways. Results: There was significant overlap of enriched DE genes between transcriptomes of AONI, CONI and neurodegeneration studies even though the overall concordance between datasets was low. The depleted DE genes identified between AONI and CONI models were significantly overlapping, but this significance did not extend to comparisons between optic nerve injury models and neurodegeneration studies. The GO terms overrepresented among the enriched genes shared between AONI, CONI and neurodegeneration studies were related to innate immune processes like the complement system and interferon signaling. KEGG pathway analysis revealed that transcriptional alteration between JAK-STAT, PI3K-AKT and TNF signaling, among others, were conserved between all models that were analyzed. Conclusions: There is a conserved transcriptional response to injury in the CNS. This transcriptional response is driven by the activation of the innate immune system and several regulatory pathways. Understanding the cellular origin of these pathways and the pathological consequences of their activation is essential for understanding and treating neurodegenerative disease.

Combinations of Osmolytes, Including Monosaccharides, Disaccharides, and Sugar Alcohols Act in Concert During Cryopreservation to Improve Mesenchymal Stromal Cell Survival.

There is demand for non-dimethyl sulfoxide (DMSO) cryoprotective agents that maintain cell viability without causing poor postthaw function or systemic toxicity. The focus of this investigation involves expanding our understanding of multicomponent osmolyte solutions and their ability to preserve cell viability during freezing. Controlled cooling rate freezing, Raman microscopy, and differential scanning calorimetry (DSC) were utilized to evaluate the differences in recovery and ice crystal formation behavior for solutions containing multiple cryoprotectants, including sugars, sugar alcohols, and small molecule additives. Postthaw recovery of mesenchymal stem cells (MSCs) in solutions containing multiple osmolytes have been shown to be comparable or better than that of MSCs frozen in 10% DMSO at 1°C/min when the solution composition is optimized. Maximum postthaw recovery was observed in these multiple osmolyte solutions with incubation times of up to 2 h before freezing. Raman images demonstrate large ice crystal formation in cryopreserved cells incubated for shorter periods of time (∼30 min), suggesting that longer permeation times are needed for these solutions. Recovery was dependent upon the concentration of each component in solution, and was not strongly correlated with osmolarity. It is noteworthy that the postthaw recovery varied significantly with the composition of solutions containing the same three components and this variation exhibited an inverted U-shape behavior, indicating that there may be a "sweet spot" for different combinations of osmolytes. Raman images of freezing behavior in different solution compositions were consistent with the observed postthaw recovery. Phase change behavior (solidification patterns and glass-forming tendency) did not differ for solutions with similar osmolarity, but differences in postthaw recovery suggest that biological, not physical, methods of protection are at play. Lastly, molecular substitution of glucose (a monosaccharide) for sucrose (a disaccharide) resulted in a significant drop in recovery. Taken together, the information from these studies increases our understanding of non-DMSO multicomponent cryoprotective solutions and the manner by which they enhance postthaw recovery.