@article{GarciaFernandezReinholdUeceyleretal.2023,
  author    = {Garc{\´i}a-Fern{\´a}ndez, Patricia and Reinhold, Colette and {\"U}{\c{c}}eyler, Nurcan and Sommer, Claudia},
  title     = {Local inflammatory mediators involved in neuropathic pain},
  series = {International Journal of Molecular Sciences},
  volume    = {24},
  journal   = {International Journal of Molecular Sciences},
  number    = {9},
  issn      = {1422-0067},
  doi       = {10.3390/ijms24097814},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313613},
  year      = {2023},
  abstract  = {Polyneuropathy (PNP) is a term to describe diseases of the peripheral nervous system, 50\% of which present with neuropathic pain. In some types of PNP, pain is restricted to the skin distally in the leg, suggesting a local regulatory process leading to pain. In this study, we proposed a pro-inflammatory pathway mediated by NF-κB that might be involved in the development of pain in patients with painful PNP. To test this hypothesis, we have collected nerve and skin samples from patients with different etiologies and levels of pain. We performed RT-qPCR to analyze the gene expression of the proposed inflammatory pathway components in sural nerve and in distal and proximal skin samples. In sural nerve, we showed a correlation of TLR4 and TNFα to neuropathic pain, and an upregulation of TNFα in patients with severe pain. Patients with an inflammatory PNP also presented a lower expression of TRPV1 and SIRT1. In distal skin, we found a reduced expression of TLR4 and miR-146-5p, in comparison to proximal skin. Our findings thus support our hypothesis of local inflammatory processes involved in pain in PNP, and further show disturbed anti-inflammatory pathways involving TRPV1 and SIRT1 in inflammatory PNP.},
  language  = {en}
}
@article{UeceylerSchliesserEvdokimovetal.2022,
  author    = {{\"U}{\c{c}}eyler, Nurcan and Schließer, Mira and Evdokimov, Dimitar and Radziwon, Jakub and Feulner, Betty and Unterecker, Stefan and Rimmele, Florian and Walter, Uwe},
  title     = {Reduced midbrain raphe echogenicity in patients with fibromyalgia syndrome},
  series = {PloS One},
  volume    = {17},
  journal   = {PloS One},
  number    = {11},
  doi       = {10.1371/journal.pone.0277316},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300639},
  year      = {2022},
  abstract  = {Objectives The pathogenesis of fibromyalgia syndrome (FMS) is unclear. Transcranial ultrasonography revealed anechoic alteration of midbrain raphe in depression and anxiety disorders, suggesting affection of the central serotonergic system. Here, we assessed midbrain raphe echogenicity in FMS. Methods Sixty-six patients underwent transcranial sonography, of whom 53 were patients with FMS (27 women, 26 men), 13 patients with major depression and physical pain (all women), and 14 healthy controls (11 women, 3 men). Raphe echogenicity was graded visually as normal or hypoechogenic, and quantified by digitized image analysis, each by investigators blinded to the clinical diagnosis. Results Quantitative midbrain raphe echogenicity was lower in patients with FMS compared to healthy controls (p<0.05), but not different from that of patients with depression and accompanying physical pain. Pain and FMS symptom burden did not correlate with midbrain raphe echogenicity as well as the presence and severity of depressive symptoms. Conclusion We found reduced echogenicity of the midbrain raphe area in patients with FMS and in patients with depression and physical pain, independent of the presence or severity of pain, FMS, and depressive symptoms. Further exploration of this sonographic finding is necessary before this objective technique may enter diagnostic algorithms in FMS and depression.},
  language  = {en}
}
@article{EvdokimovDinkelFranketal.2020,
  author    = {Evdokimov, Dimitar and Dinkel, Philine and Frank, Johanna and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Characterization of dermal skin innervation in fibromyalgia syndrome},
  series = {PLoS One},
  volume    = {15},
  journal   = {PLoS One},
  number    = {1},
  doi       = {10.1371/journal.pone.0227674},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229299},
  year      = {2020},
  abstract  = {Introduction We characterized dermal innervation in patients with fibromyalgia syndrome (FMS) as potential contribution to small fiber pathology. Methods Skin biopsies of the calf were collected (86 FMS patients, 35 healthy controls). Skin was immunoreacted with antibodies against protein gene product 9.5, calcitonine gene-related peptide, substance P, CD31, and neurofilament 200 for small fiber subtypes. We assessed two skin sections per patient; on each skin section, two dermal areas (150 x 700 mu m each) were investigated for dermal nerve fiber length (DNFL). Results In FMS patients we found reduced DNFL of fibers with vessel contact compared to healthy controls (p<0.05). There were no differences for the other nerve fiber subtypes. Discussion We found less dermal nerve fibers in contact with blood vessels in FMS patients than in controls. The pathophysiological relevance of this finding is unclear, but we suggest the possibility of a relationship with impaired thermal tolerance commonly reported by FMS patients.},
  language  = {en}
}
@article{KlitschEvdokimovFranketal.2020,
  author    = {Klitsch, Alexander and Evdokimov, Dimitar and Frank, Johanna and Thomas, Dominique and Saffer, Nadine and Meyer zu Altenschildesche, Caren and Sisignano, Marco and Kampik, Daniel and Malik, Rayaz A. and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Reduced association between dendritic cells and corneal sub-basal nerve fibers in patients with fibromyalgia syndrome},
  series = {Journal of the Peripheral Nervous System},
  volume    = {25},
  journal   = {Journal of the Peripheral Nervous System},
  number    = {1},
  doi       = {10.1111/jns.12360},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214150},
  pages     = {9-18},
  year      = {2020},
  abstract  = {In our study, we aimed at investigating corneal langerhans cells (LC) in patients with fibromyalgia syndrome (FMS) and small fiber neuropathy (SFN) as potential contributors to corneal small fiber pathology. We enrolled women with FMS (n = 134) and SFN (n = 41) who underwent neurological examination, neurophysiology, prostaglandin analysis in tear fluid, and corneal confocal microscopy (CCM). Data were compared with those of 60 age-matched female controls. After screening for dry eye disease, corneal LC were counted and sub-classified as dendritic (dLC) and non-dendritic (ndLC) cells with or without nerve fiber association. We further analyzed corneal nerve fiber density (CNFD), length (CNFL), and branch density (CNBD). Neurological examination indicated deficits of small fiber function in patients with SFN. Nerve conduction studies were normal in all participants. Dry eye disease was more prevalent in FMS (17\%) and SFN (28\%) patients than in controls (5\%). Tear fluid prostaglandin levels did not differ between FMS patients and controls. While corneal LC density in FMS and SFN patients was not different from controls, there were fewer dLC in association with nerve fibers in FMS and SFN patients than in controls (P < .01 each). Compared to controls, CNFL was lower in FMS and SFN patients (P < .05 each), CNFD was lower only in FMS patients (P < .05), and CNBD was lower only in SFN patients (P < .001). There was no difference in any CCM parameter between patients with and without dry eyes. Our data indicate changes in corneal innervation and LC distribution in FMS and SFN, potentially based on altered LC signaling.},
  language  = {en}
}
@article{UeceylerBikoHoseetal.2016,
  author    = {{\"U}{\c{c}}eyler, Nurcan and Biko, Lydia and Hose, Dorothea and Hoffmann, Lukas and Sommer, Claudia},
  title     = {Comprehensive and differential long-term characterization of the alpha-galactosidase A deficient mouse model of Fabry disease focusing on the sensory system and pain development},
  series = {Molecular Pain},
  volume    = {12},
  journal   = {Molecular Pain},
  number    = {1744806916646370},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147562},
  year      = {2016},
  abstract  = {Fabry disease is an X-linked lysosomal storage disorder due to impaired activity of alpha-galactosidase A with intracellular accumulation of globotriaosylceramide. Associated small fiber pathology leads to characteristic pain in Fabry disease. We systematically assessed sensory system, physical activity, metabolic parameters, and morphology of male and female mice with alpha-galactosidase A deficiency (Fabry ko) from 2 to 27 months of age and compared results with those of age- and gender-matched wild-type littermates of C57Bl/6J background. Results From the age of two months, male and female Fabry mice showed mechanical hypersensitivity (p < 0.001 each) compared to wild-type littermates. Young Fabry ko mice of both genders were hypersensitive to heat stimulation (p < 0.01) and developed heat hyposensitivity with aging (p < 0.05), while cold hyposensitivity was present constantly in young (p < 0.01) and old (p < 0.05) Fabry ko mice compared to wild-type littermates. Stride angle increased only in male Fabry ko mice with aging (p < 0.01) in comparison to wild-type littermates. Except for young female mice, male (p < 0.05) and female (p < 0.01) Fabry ko mice had a higher body weight than wild-type littermates. Old male Fabry ko mice were physically less active than their wild-type littermates (p < 0.05), had lower chow intake (p < 0.001), and lost more weight (p < 0.001) in a one-week treadmill experiment than wild-type littermates. Also, Fabry ko mice showed spontaneous pain protective behavior and developed orofacial dysmorphism resembling patients with Fabry disease. Conclusions. Mice with alpha-galactosidase A deficiency show age-dependent and distinct deficits of the sensory system. alpha-galactosidase A-deficient mice seem to model human Fabry disease and may be helpful when studying the pathophysiology of Fabry-associated pain.},
  language  = {en}
}
@article{UeceylerKewenigKittelSchneideretal.2015,
  author    = {{\"U}{\c{c}}eyler, Nurcan and Kewenig, Susanne and Kittel-Schneider, Sarah and Fallgatter, Andreas J. and Sommer, Claudia},
  title     = {Increased cortical activation upon painful stimulation in fibromyalgia syndrome},
  series = {BMC Neurology},
  volume    = {15},
  journal   = {BMC Neurology},
  number    = {210},
  doi       = {10.1186/s12883-015-0472-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125230},
  year      = {2015},
  abstract  = {Background Fibromyalgia syndrome (FMS) is a chronic condition characterized by widespread pain and associated symptoms. We investigated cerebral activation in FMS patients by functional near-infrared spectroscopy (fNIRS). Methods Two stimulation paradigms were applied: a) painful pressure stimulation at the dorsal forearm; b) verbal fluency test (VFT). We prospectively recruited 25 FMS patients, ten patients with unipolar major depression (MD) without pain, and 35 healthy controls. All patients underwent neurological examination and all subjects were investigated with questionnaires (pain, depression, FMS, empathy). Results FMS patients had lower pressure pain thresholds than patients with MD and controls (p < 0.001) and reported higher pain intensity (p < 0.001). Upon unilateral pressure pain stimulation fNIRS recordings revealed increased bilateral cortical activation in FMS patients compared to controls (p < 0.05). FMS patients also displayed a stronger contralateral activity over the dorsolateral prefrontal cortex in direct comparison to patients with MD (p < 0.05). While all three groups performed equally well in the VFT, a frontal deficit in cortical activation was only found in patients with depression (p < 0.05). Performance and cortical activation correlated negatively in FMS patients (p < 0.05) and positively in patients with MD (p < 0.05). Conclusion Our data give further evidence for altered central nervous processing in patients with FMS and the distinction between FMS and MD.},
  language  = {en}
}