Browsing by Author "Guthoff, Rudolf F."

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    Assessment of dynamic corneal nerve changes using static landmarks by in vivo large-area confocal microscopy—a longitudinal proof-of-concept study
    (AME Publishing Company, 2022) Stache, Nadine; Sterenczak, Katharina A.; Sperlich, Karsten; Marfurt, Carl F.; Allgeier, Stephan; Köhler, Bernd; Mikut, Ralf; Bartschat, Andreas; Reichert, Klaus-Martin; Guthoff, Rudolf F.; Stachs, Angrit; Stachs, Oliver; Bohn, Sebastian; Anatomy, Cell Biology and Physiology, School of Medicine
    Background: The purpose of the present proof-of-concept study was to use large-area in vivo confocal laser scanning microscopy (CLSM) mosaics to determine the migration rates of nerve branching points in the human corneal subbasal nerve plexus (SNP). Methods: Three healthy individuals were examined roughly weekly over a total period of six weeks by large-area in vivo confocal microscopy of the central cornea. An in-house developed prototype system for guided eye movement with an acquisition time of 40 s was used to image and generate large-area mosaics of the SNP. Kobayashi-structures and nerve entry points (EPs) were used as fixed structures to enable precise mosaic registration over time. The migration rate of 10 prominent nerve fiber branching points per participant was tracked and quantified over the longitudinal period. Results: Total investigation times of 10 minutes maximum per participant were used to generate mosaic images with an average size of 3.61 mm2 (range: 3.18-4.42 mm2). Overall mean branching point migration rates of (46.4±14.3), (48.8±15.5), and (50.9±13.9) µm/week were found for the three participants with no statistically significant difference. Longitudinal analyses of nerve branching point migration over time revealed significant time-dependent changes in migration rate only in participant 3 between the last two measurements [(63.7±12.3) and (43.0±12.5) µm/week, P<0.01]. Considering individual branching point dynamics, significant differences in nerve migration rate from the mean were only found in a few exceptions. Conclusions: The results of this proof-of-concept study have demonstrated the feasibility of using in vivo confocal microscopy to study the migration rates of corneal subbasal nerves within large areas of the central human cornea (>1 mm2). The ability to monitor dynamic changes in the SNP opens a window to future studies of corneal nerve health and regenerative capacity in a number of systemic and ocular diseases. Since corneal nerves are considered part of the peripheral nervous system, this technique could also offer an objective diagnostic tool and biomarker for disease- or treatment-induced neuropathic changes.
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    Atypical Cellular Elements of Unknown Origin in the Subbasal Nerve Plexus of a Diabetic Cornea Diagnosed by Large-Area Confocal Laser Scanning Microscopy
    (MDPI, 2021-01-21) Sterenczak, Katharina A.; Stachs, Oliver; Marfurt, Carl; Matuszewska-Iwanicka, Aleksandra; Stratmann, Bernd; Sperlich, Karsten; Guthoff, Rudolf F.; Hettlich, Hans-Joachim; Allgeier, Stephan; Stahnke, Thomas; Anatomy and Cell Biology, School of Medicine
    In vivo large-area confocal laser scanning microscopy (CLSM) of the human eye using EyeGuidance technology allows a large-scale morphometric assessment of the corneal subbasal nerve plexus (SNP). Here, the SNP of a patient suffering from diabetes and associated late complications was analyzed. The SNP contained multiple clusters of large hyperintense, stellate-shaped, cellular-like structures. Comparable structures were not observed in control corneas from healthy volunteers. Two hypotheses regarding the origin of these atypical structures are proposed. First, these structures might be keratocyte-derived myofibroblasts that entered the epithelium from the underlying stroma through breaks in Bowman's layer. Second, these structures could be proliferating Schwann cells that entered the epithelium in association with subbasal nerves. The nature and pathophysiological significance of these atypical cellular structures, and whether they are a direct consequence of the patient's diabetic neuropathy/or a non-specific secondary effect of associated inflammatory processes, are unknown.