In a properly contracting cardiac muscle, many different subcellular structures are organized into an intricate architecture. While it has been observed that this organization is altered in pathological conditions, the relationship between length-scales and architecture has not been properly explored. In this work, we utilize a variety of architecture metrics to quantify organization and consistency of single structures over multiple scales, from subcellular to tissue scale as well as correlation of organization of multiple structures. Specifically, as the best way to characterize cardiac tissues, we chose the orientational and co-orientational order parameters (COOPs). Similarly, neonatal rat ventricular myocytes were selected for their consistent architectural behavior. The engineered cells and tissues were stained for four architectural structures: actin, tubulin, sarcomeric z-lines, and nuclei. We applied the orientational metrics to cardiac cells of various shapes, isotropic cardiac tissues, and anisotropic globally aligned tissues. With these novel tools, we discovered: (1) the relationship between cellular shape and consistency of self-assembly; (2) the length-scales at which unguided tissues self-organize; and (3) the correlation or lack thereof between organization of actin fibrils, sarcomeric z-lines, tubulin fibrils, and nuclei. All of these together elucidate some of the current mysteries in the relationship between force production and architecture, while raising more questions about the effect of guidance cues on self-assembly function. These types of metrics are the future of quantitative tissue engineering in cardiovascular biomechanics.

Nuclear shape defects are a distinguishing characteristic in laminopathies, cancers, and other pathologies. Correlating these defects to the symptoms, mechanisms, and progression of disease requires unbiased, quantitative, and high-throughput means of quantifying nuclear morphology. To accomplish this, we developed a method of automatically segmenting fluorescently stained nuclei in 2D microscopy images and then classifying them as normal or dysmorphic based on three geometric features of the nucleus using a package of Matlab codes. As a test case, cultured skin-fibroblast nuclei of individuals possessing LMNA splice-site mutation (c.357-2A>G), LMNA nonsense mutation (c.736 C>T, pQ246X) in exon 4, LMNA missense mutation (c.1003C>T, pR335W) in exon 6, Hutchinson-Gilford Progeria Syndrome, and no LMNA mutations were analyzed. For each cell type, the percentage of dysmorphic nuclei, and other morphological features such as average nuclear area and average eccentricity were obtained. Compared to blind observers, our procedure implemented in Matlab codes possessed similar accuracy to manual counting of dysmorphic nuclei while being significantly more consistent. The automatic quantification of nuclear defects revealed a correlation between in vitro results and age of patients for initial symptom onset. Our results demonstrate the method's utility in experimental studies of diseases affecting nuclear shape through automated, unbiased, and accurate identification of dysmorphic nuclei.

PURPOSE: To describe predominantly persistent intraretinal fluid (PP-IRF) and its association with visual acuity (VA) and retinal anatomic findings at long-term follow-up in eyes treated with pro re nata (PRN) ranibizumab or bevacizumab for neovascular age-related macular degeneration. DESIGN: Cohort within a randomized clinical trial. PARTICIPANTS: Participants in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT) assigned to PRN treatment. METHODS: The presence of intraretinal fluid (IRF) on OCT scans was assessed at baseline and monthly follow-up visits by Duke OCT Reading Center. Predominantly persistent intraretinal fluid through week 12, year 1, and year 2 was defined as the presence of IRF at the baseline and in ≥ 80% of follow-up visits. Among eyes with baseline IRF, the mean VA scores (letters) and changes from the baseline were compared between eyes with and those without PP-IRF. Adjusted mean VA scores and changes from the baseline were also calculated using the linear regression analysis to account for baseline patient features identified as predictors of VA in previous CATT studies. Furthermore, outcomes were adjusted for concomitant predominantly persistent subretinal fluid. MAIN OUTCOME MEASURES: Predominantly persistent intraretinal fluid through week 12, year 1, and year 2; VA score and VA change; and scar development at year 2. RESULTS: Among 363 eyes with baseline IRF, 108 (29.8%) had PP-IRF through year 1 and 95 (26.1%) had PP-IRF through year 2. When eyes with PP-IRF through year 1 were compared with those without PP-IRF, the mean 1-year VA score was 62.4 and 68.5, respectively (P = 0.002), and was 65.0 and 67.4, respectively (P = 0.13), after adjustment. Predominantly persistent intraretinal fluid through year 2 was associated with worse adjusted 1-year mean VA scores (64.8 vs. 69.2; P = 0.006) and change (4.3 vs. 8.1; P = 0.01) as well as worse adjusted 2-year mean VA scores (63.0 vs. 68.3; P = 0.004) and changes (2.4 vs. 7.1; P = 0.009). Predominantly persistent intraretinal fluid through year 2 was associated with a higher 2-year risk of scar development (adjusted hazard ratio = 1.49; P = 0.03). CONCLUSIONS: Approximately one quarter of eyes had PP-IRF through year 2. Predominantly persistent intraretinal fluid through year 1 was associated with worse long-term VA, but the relationship disappeared after adjustment for baseline predictors of VA. Predominantly persistent intraretinal fluid through year 2 was independently associated with worse long-term VA and scar development.