Corneal nerve fiber assessment proposed for managing patients with HIV-induced peripheral neuropathy, according to The American Journal of Pathology
Corneal nerve fiber assessment has great potential as a tool to diagnose and monitor peripheral neuropathy induced by HIV, say scientists at the Johns Hopkins University School of Medicine. The results of their study are published in The American Journal of Pathology.
Although corneal nerve assessments have shown increasingly valuable as a replacement for epidermal nerve fiber evaluation in diabetic peripheral neuropathy, the evaluation of corneal alterations in tracking HIV-induced neuropathy has yet to be explored.
"The cornea is the most densely innervated tissue in the body, so corneal nerve assessment is extremely sensitive for detecting small sensory nerve fiber damage as compared to other tests including measurement of intra-epidermal nerve fibers in the skin," notes lead investigator Joseph L. Mankowski, DVM, PhD, who is Professor of Molecular and Comparative Pathobiology, Pathology, and Neurology at the Johns Hopkins University School of Medicine, Baltimore, MD.
Although not life threatening, HIV-induced peripheral neuropathy greatly compromises patient quality of life. Currently, skin biopsy is the accepted standard for measuring the loss of small, unmyelinated C fibers in the epidermis, one of the earliest detectable signs of peripheral nerve damage. However, skin biopsy is an invasive procedure, and ongoing assessment requires repeated surgical procedures.
Electrophysiological testing to measure peripheral nerve conduction properties is not a viable alternative because current methods lack the sensitivity required to detect damage to small, unmyelinated fibers, especially in early stages of disease. Therefore, new sensitive, noninvasive methods of assessing small fiber nerve damage are urgently needed to detect and monitor peripheral neuropathy in HIV-infected individuals.
To study the pathogenesis of HIV-induced PNS disease, Jamie Dorsey, Research Technologist, and the research team led by Dr. Mankowski developed a simian immunodeficiency virus (SIV)-infected macaque model that closely reflects key peripheral nervous system (PNS) alterations seen in HIV patients with peripheral neuropathy. They sought to determine whether SIV infection leads to decreases in corneal nerve fiber density, and whether corneal nerve fiber density correlates with epidermal nerve fiber length counts, thereby setting the stage for follow-up investigation using corneal confocal microscopy.
"Moving to non-invasive and repeatable methods of nerve fiber measurements such as in vivo corneal confocal microscopy would enhance study of peripheral neuropathy by enabling early detection of damage, progression of nerve fiber deterioration, and enable assessment of therapeutic strategies in the SIV/macaque model," explains Dr. Mankowski. "Furthermore, adapting in vivo corneal confocal microscopy for use in tracking HIV-induced PNS damage in patients may be of great value to identify early PNS damage independent of performing skin biopsies."
To determine whether SIV infection leads to corneal nerve fiber loss, the researchers immunostained corneas for the nerve fiber marker βIII tubulin. They developed and applied both manual and automated methods developed by Jonathan Oakley, PhD, of Voxeleron to measure nerves in the corneal sub-basal plexus. These counting methods independently demonstrated significantly lower sub-basal corneal nerve fiber density among SIV-infected animals that rapidly progressed to AIDS as compared to slow progressors. Corneal nerve fiber density was also directly correlated with epidermal nerve fiber length.
Besides decreased corneal nerve fiber density, rapid SIV progressors had increased levels of SIV RNA, CD68-positive macrophages, and GFAP expression by glial satellite cells in the trigeminal ganglia, the location of the neuronal cell bodies of corneal sensory nerve fibers.
Together, these findings demonstrate that emerging noninvasive techniques to measure corneal nerve fiber alterations such as in vivo corneal confocal microscopy may be useful clinical tools to screen for and monitor progression of peripheral neuropathy in HIV-infected patients.
Eileen Leahy | Eurek Alert!
Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State
NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences