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!
A promising target for kidney fibrosis
21.04.2017 | Brigham and Women's Hospital
Stem cell transplants: activating signal paths may protect from graft-versus-host disease
20.04.2017 | Technische Universität München
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences