@article{EgenolfAltenschildescheKressetal.2021,
  author    = {Egenolf, Nadine and Altenschildesche, Caren Meyer zu and Kreß, Luisa and Eggermann, Katja and Namer, Barbara and Gross, Franziska and Klitsch, Alexander and Malzacher, Tobias and Kampik, Daniel and Malik, Rayaz A. and Kurth, Ingo and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Diagnosing small fiber neuropathy in clinical practice: a deep phenotyping study},
  series = {Therapeutic Advances in Neurological Disorders},
  volume    = {14},
  journal   = {Therapeutic Advances in Neurological Disorders},
  issn      = {1756-2864},
  doi       = {10.1177/17562864211004318},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232019},
  year      = {2021},
  abstract  = {Background and aims: Small fiber neuropathy (SFN) is increasingly suspected in patients with pain of uncertain origin, and making the diagnosis remains a challenge lacking a diagnostic gold standard. Methods: In this case-control study, we prospectively recruited 86 patients with a medical history and clinical phenotype suggestive of SFN. Patients underwent neurological examination, quantitative sensory testing (QST), and distal and proximal skin punch biopsy, and were tested for pain-associated gene loci. Fifty-five of these patients additionally underwent pain-related evoked potentials (PREP), corneal confocal microscopy (CCM), and a quantitative sudomotor axon reflex test (QSART). Results: Abnormal distal intraepidermal nerve fiber density (IENFD) (60/86, 70\%) and neurological examination (53/86, 62\%) most frequently reflected small fiber disease. Adding CCM and/or PREP further increased the number of patients with small fiber impairment to 47/55 (85\%). Genetic testing revealed potentially pathogenic gene variants in 14/86 (16\%) index patients. QST, QSART, and proximal IENFD were of lower impact. Conclusion: We propose to diagnose SFN primarily based on the results of neurological examination and distal IENFD, with more detailed phenotyping in specialized centers.},
  language  = {en}
}
@article{HartmannsbergerDopplerStauberetal.2020,
  author    = {Hartmannsberger, Beate and Doppler, Kathrin and Stauber, Julia and Schlotter-Weigel, Beate and Young, Peter and Sereda, Michael W. and Sommer, Claudia},
  title     = {Intraepidermal nerve fiber density as biomarker in Charcot-Marie-Tooth disease 1A},
  series = {Brain Communications},
  volume    = {2},
  journal   = {Brain Communications},
  number    = {1},
  doi       = {10.1093/braincomms/fcaa012},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229538},
  year      = {2020},
  abstract  = {Charcot-Marie-Tooth disease type 1A, caused by a duplication of the gene peripheral myelin protein 22 kDa, is the most frequent subtype of hereditary peripheral neuropathy with an estimated prevalence of 1:5000. Patients suffer from sensory deficits, muscle weakness and foot deformities. There is no treatment approved for this disease. Outcome measures in clinical trials were based mainly on clinical features but did not evaluate the actual nerve damage. In our case-control study, we aimed to provide objective and reproducible outcome measures for future clinical trials. We collected skin samples from 48 patients with Charcot-Marie-Tooth type 1A, 7 patients with chronic inflammatory demyelinating polyneuropathy, 16 patients with small fibre neuropathy and 45 healthy controls. To analyse skin innervation, 40-µm cryosections of glabrous skin taken from the lateral index finger were double-labelled by immunofluorescence. The disease severity of patients with Charcot-Marie-Tooth type 1A was assessed by the Charcot-Marie-Tooth neuropathy version 2 score, which ranged from 3 (mild) to 27 (severe) and correlated with age (P < 0.01, R = 0.4). Intraepidermal nerve fibre density was reduced in patients with Charcot-Marie-Tooth type 1A compared with the healthy control group (P < 0.01) and negatively correlated with disease severity (P < 0.05, R = -0.293). Meissner corpuscle (MC) density correlated negatively with age in patients with Charcot-Marie-Tooth type 1A (P < 0.01, R = -0.45) but not in healthy controls (P = 0.07, R = 0.28). The density of Merkel cells was reduced in patients with Charcot-Marie-Tooth type 1A compared with healthy controls (P < 0.05). Furthermore, in patients with Charcot-Marie-Tooth type 1A, the fraction of denervated Merkel cells was highly increased and correlated with age (P < 0.05, R = 0.37). Analysis of nodes of Ranvier revealed shortened paranodes and a reduced fraction of long nodes in patients compared with healthy controls (both P < 0.001). Langerhans cell density was increased in chronic inflammatory demyelinating polyneuropathy, but not different in Charcot-Marie-Tooth type 1A compared with healthy controls. Our data suggest that intraepidermal nerve fibre density might be used as an outcome measure in Charcot-Marie-Tooth type 1A disease, as it correlates with disease severity. The densities of Meissner corpuscles and Merkel cells might be an additional tool for the evaluation of the disease progression. Analysis of follow-up biopsies will clarify the effects of Charcot-Marie-Tooth type 1A disease progression on cutaneous innervation.},
  language  = {en}
}
@article{OezdağAcarlıKleinEgenolfetal.2022,
  author    = {{\"O}zdağ Acarl{\i}, Ay{\c{s}}e Nur and Klein, Thomas and Egenolf, Nadine and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Subepidermal Schwann cell counts correlate with skin innervation - an exploratory study},
  series = {Muscle \& Nerve},
  volume    = {65},
  journal   = {Muscle \& Nerve},
  number    = {4},
  doi       = {10.1002/mus.27496},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318726},
  pages     = {471 -- 479},
  year      = {2022},
  abstract  = {Introduction/Aims Schwann cell clusters have been described at the murine dermis-epidermis border. We quantified dermal Schwann cells in the skin of patients with small-fiber neuropathy (SFN) compared with healthy controls to correlate with the clinical phenotype. Methods Skin punch biopsies from the lower legs of 28 patients with SFN (11 men, 17 women; median age, 54 [range, 19-73] years) and 9 healthy controls (five men, four women, median age, 34 [range, 25-69] years) were immunoreacted for S100 calcium-binding protein B as a Schwann cell marker, protein-gene product 9.5 as a pan-neuronal marker, and CD207 as a Langerhans cell marker. Intraepidermal nerve fiber density (IENFD) and subepidermal Schwann cell counts were determined. Results Skin samples of patients with SFN showed lower IENFD (P < .05), fewer Schwann cells per millimeter (P < .01), and fewer Schwann cell clusters per millimeter (P < .05) than controls. When comparing SFN patients with reduced (n = 13; median age, 53 [range, 19-73] years) and normal distal (n = 15, median age, 54 [range, 43-68] years) IENFD, the number of solitary Schwann cells per millimeter (p < .01) and subepidermal nerve fibers associated with Schwann cell branches (P < .05) were lower in patients with reduced IENFD. All three parameters correlated positively with distal IENFD (P < .05 to P < .01), whereas no correlation was found between Schwann cell counts and clinical pain characteristics. Discussion Our data raise questions about the mechanisms underlying the interdependence of dermal Schwann cells and skin innervation in SFN. The temporal course and functional impact of Schwann cell presence and kinetics need further investigation.},
  language  = {en}
}
@article{HartmannsbergerScribaGuidolinetal.2024,
  author    = {Hartmannsberger, Beate and Scriba, Sabrina and Guidolin, Carolina and Becker, Juliane and Mehling, Katharina and Doppler, Kathrin and Sommer, Claudia and Rittner, Heike L.},
  title     = {Transient immune activation without loss of intraepidermal innervation and associated Schwann cells in patients with complex regional pain syndrome},
  series = {Journal of Neuroinflammation},
  volume    = {21},
  journal   = {Journal of Neuroinflammation},
  doi       = {10.1186/s12974-023-02969-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357164},
  year      = {2024},
  abstract  = {Background Complex regional pain syndrome (CRPS) develops after injury and is characterized by disproportionate pain, oedema, and functional loss. CRPS has clinical signs of neuropathy as well as neurogenic inflammation. Here, we asked whether skin biopsies could be used to differentiate the contribution of these two systems to ultimately guide therapy. To this end, the cutaneous sensory system including nerve fibres and the recently described nociceptive Schwann cells as well as the cutaneous immune system were analysed. Methods We systematically deep-phenotyped CRPS patients and immunolabelled glabrous skin biopsies from the affected ipsilateral and non-affected contralateral finger of 19 acute (< 12 months) and 6 chronic (> 12 months after trauma) CRPS patients as well as 25 sex- and age-matched healthy controls (HC). Murine foot pads harvested one week after sham or chronic constriction injury were immunolabelled to assess intraepidermal Schwann cells. Results Intraepidermal Schwann cells were detected in human skin of the finger—but their density was much lower compared to mice. Acute and chronic CRPS patients suffered from moderate to severe CRPS symptoms and corresponding pain. Most patients had CRPS type I in the warm category. Their cutaneous neuroglial complex was completely unaffected despite sensory plus signs, e.g. allodynia and hyperalgesia. Cutaneous innate sentinel immune cells, e.g. mast cells and Langerhans cells, infiltrated or proliferated ipsilaterally independently of each other—but only in acute CRPS. No additional adaptive immune cells, e.g. T cells and plasma cells, infiltrated the skin. Conclusions Diagnostic skin punch biopsies could be used to diagnose individual pathophysiology in a very heterogenous disease like acute CRPS to guide tailored treatment in the future. Since numbers of inflammatory cells and pain did not necessarily correlate, more in-depth analysis of individual patients is necessary.},
  language  = {en}
}
@phdthesis{Frank2019,
  author    = {Frank, Johanna},
  title     = {Untersuchung der Kleinfaserpathologie beim Fibromyalgie-Syndrom},
  publisher = {Annals of Neurology, The Journal of Rheumatology},
  doi       = {10.25972/OPUS-19265},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-192653},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Die Studienergebnisse st{\"u}tzen das Konzept, dass das periphere Nervensystem zu Schmerzen beim Fibromyalgie-Syndrom (FMS) beitr{\"a}gt. An der Neurologischen Universit{\"a}tsklinik W{\"u}rzburg wurden 53 FMS Patientinnen und 35 gesunde Kontrollen rekrutiert, ausf{\"u}hrlich anamnestiziert inklusive spezieller Schmerzfrageb{\"o}gen, neurologisch und mittels spezieller Tests auf eine St{\"o}rung der kleinkalibrigen A-delta- und C-Nervenfasern untersucht. Hierzu geh{\"o}rte eine quantitative sensorische Testung mit Pleasant touch Untersuchung und die schmerz-assoziierten elektrisch-evoziierten Potentiale f{\"u}r die Kleinfaserfunktion und die corneale confocale Mikroskopie, sowie die Analyse von Hautstanbiopsien f{\"u}r die Kleinfasermorphologie. Im Unterschied zu gesunden Kontrollen wiesen die FMS Patientinnen eine Reduktion, als auch eine Funktions{\"a}nderung der kleinkalibrigen Nervenfasern auf. Des Weiteren konnten wir aus der heterogenen Patientenpopulation anhand von unterschiedlichen Nervenfaserdichten der Haut eine Subgruppe mit generalisierter Reduktion der Hautinnervation identifizieren, die besonders schwer betroffen ist. Diese Subgruppenanalysen k{\"o}nnen k{\"u}nftig von großer Bedeutung f{\"u}r die Therapiewahl sein.},
  subject      = {Fibromyalgie},
  language  = {de}
}