Browsing by Subject "Nerve Fibers"

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    Baseline structural characteristics of the optic nerve head and retinal nerve fiber layer are associated with progressive visual field loss in patients with open-angle glaucoma
    (Public Library of Science, 2020-08-20) Siesky, Brent; Wentz, Scott M.; Januleviciene, Ingrida; Kim, Daniel H.; Burgett, Kendall M.; Vercellin, Alice C. Verticchio; Rowe, Lucas W.; Eckert, George J.; Harris, Alon; Biostatistics, School of Public Health
    Aims To examine the relationship between baseline structural characteristics of the optic nerve head (ONH) and retinal nerve fiber layer (RNFL) and functional disease progression in patients with open-angle glaucoma (OAG) over 5 years. Methods 112 OAG patients were prospectively examined at baseline and every 6 months over a period of five years. Structural glaucomatous changes were examined with optical coherence tomography (OCT) and Heidelberg retinal tomography-III (HRT-III), and functional disease progression with automated perimetry (Humphrey visual fields). Cox proportional hazard models were used to assess the relationship between baseline structural measurements and functional disease progression. Results From baseline over a 5-year period, statistically significant increases were found in OCT disc (D) area (p<0.001), cup (C) area (p<0.001), C/D area ratio (p<0.001), C/D horizontal ratio (p<0.001), C/D vertical ratio (p = 0.018), and a decrease in superior RNFL thickness (p = 0.008). Statistically significant increases were found in HRT-III C volume (p = 0.021), C/D area ratio (p = 0.046), mean C depth (p = 0.036), C shape (p = 0.008), and height variation contour (p = 0.020). Functional disease progression was detected in 37 of the 112 patients (26 of European descent and 11 of African descent; 33%). A statistically significant shorter time to functional progression was seen in patients with larger baseline OCT D area (p = 0.008), C area (p = 0.003), thicker temporal RNFL (p = 0.003), and in patients with a larger HRT-III C area (p = 0.004), C/D area ratio (p = 0.004), linear C/D ratio (p = 0.007), C shape (p = 0.032), or smaller rim area (p = 0.039), rim volume (p = 0.005), height variation contour (p = 0.041), mean RNFL thickness (p<0.001), or RNFL cross-sectional area (p = 0.002). Conclusion Baseline ONH and RNFL structural characteristics were associated with a significantly shorter time to functional glaucomatous progression and visual field loss through the five-year period in OAG patients.
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    Loss of Corneal Sensory Nerve Fibers in SIV-Infected Macaques: An Alternate Approach to Investigate HIV-Induced PNS Damage
    (Elsevier B.V., 2014-06) Dorsey, Jamie L.; Mangus, Lisa M.; Oakley, Jonathan D.; Beck, Sarah E.; Kelly, Kathleen M.; Queen, Suzanne E.; Metcalf Pate, Kelly A.; Adams, Robert J.; Marfurt, Carl F.; Mankowski, Joseph L.; Department of Anatomy & Cell Biology, IU School of Medicine
    Peripheral neuropathy is the most frequent neurological complication of HIV infection, affecting more than one-third of infected patients, including patients treated with antiretroviral therapy. Although emerging noninvasive techniques for corneal nerve assessments are increasingly being used to diagnose and monitor peripheral neuropathies, corneal nerve alterations have not been characterized in HIV. Here, to determine whether SIV infection leads to corneal nerve fiber loss, we immunostained corneas for the nerve fiber marker βIII tubulin. We developed and applied both manual and automated methods to measure nerves in the corneal subbasal plexus. These counting methods independently indicated significantly lower subbasal corneal nerve fiber density among SIV-infected animals that rapidly progressed to AIDS compared with slow progressors. Concomitant with decreased corneal nerve fiber density, rapid progressors had increased levels of SIV RNA and CD68-positive macrophages and expression of glial fibrillary acidic protein by glial satellite cells in the trigeminal ganglia, the location of the neuronal cell bodies of corneal sensory nerve fibers. In addition, corneal nerve fiber density was directly correlated with epidermal nerve fiber length. These findings indicate that corneal nerve assessment has great potential to diagnose and monitor HIV-induced peripheral neuropathy and to set the stage for introducing noninvasive techniques to measure corneal nerve fiber density in HIV clinical settings.
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    Sympathetic Nerve Fibers in Human Cervical and Thoracic Vagus Nerves
    (Els, 2014-08) Seki, Atsuko; Green, Hunter R.; Lee, Thomas D.; Hong, LongSheng; Tan, Jian; Vinters, Harry V.; Chen, Peng-Sheng; Fishbein, Michael C.; Department of Medicine, IU School of Medicine
    Background Vagus nerve stimulation therapy (VNS) has been used for chronic heart failure (CHF), and is believed to improve imbalance of autonomic control by increasing parasympathetic activity. Although it is known that there is neural communication between the VN and the cervical sympathetic trunk, there are few data regarding the quantity and/or distribution of the sympathetic components within the VN. Objective To examine the sympathetic component within human VN and correlate these with the presence of cardiac and neurologic diseases. Methods We performed immunohistochemistry on 31 human cervical and thoracic VNs (total 104 VNs) from autopsies and we reviewed the patients’ records. We correlated the quantity of sympathetic nerve fibers within the VNs with cardiovascular and neurologic disease states. Results All 104 VNs contain TH positive (sympathetic) nerve fibers; the mean TH positive areas were 5.47% in right cervical, 3.97% in left cervical, 5.11% in right thoracic, and 4.20% in left thoracic VN. The distribution of TH positive nerve fibers varied from case to case: central, peripheral, or scattered throughout nerve bundles. No statistically significant differences in nerve morphology were seen between diseases in which VNS is considered effective (depression and CHF), and other cardiovascular diseases, or neurodegenerative disease. Conclusion Human VNs contain sympathetic nerve fibers. The sympathetic component within the VN could play a role in physiologic effects reported with VNS. The recognition of sympathetic nerve fibers in the VNs may lead to better understanding of the therapeutic mechanisms of VNS.