TY  - JOUR
A1  - Reinhold, Ann Kristin
A1  - Krug, Susanne M.
A1  - Salvador, Ellaine
A1  - Sauer, Reine S.
A1  - Karl-Schöller, Franziska
A1  - Malcangio, Marzia
A1  - Sommer, Claudia
A1  - Rittner, Heike L.
T1  - MicroRNA-21-5p functions via RECK/MMP9 as a proalgesic regulator of the blood nerve barrier in nerve injury
JF  - Annals of the New York Academy of Sciences
N2  - Both nerve injury and complex regional pain syndrome (CRPS) can result in chronic pain. In traumatic neuropathy, the blood nerve barrier (BNB) shielding the nerve is impaired—partly due to dysregulated microRNAs (miRNAs). Upregulation of microRNA-21-5p (miR-21) has previously been documented in neuropathic pain, predominantly due to its proinflammatory features. However, little is known about other functions. Here, we characterized miR-21 in neuropathic pain and its impact on the BNB in a human-murine back translational approach. MiR-21 expression was elevated in plasma of patients with CRPS as well as in nerves of mice after transient and persistent nerve injury. Mice presented with BNB leakage, as well as loss of claudin-1 in both injured and spared nerves. Moreover, the putative miR-21 target RECK was decreased and downstream Mmp9 upregulated, as was Tgfb. In vitro experiments in human epithelial cells confirmed a downregulation of CLDN1 by miR-21 mimics via inhibition of the RECK/MMP9 pathway but not TGFB. Perineurial miR-21 mimic application in mice elicited mechanical hypersensitivity, while local inhibition of miR-21 after nerve injury reversed it. In summary, the data support a novel role for miR-21, independent of prior inflammation, in elicitation of pain and impairment of the BNB via RECK/MMP9.
KW  - claudin-1
KW  - RECK
KW  - MMP9
KW  - CRPS
KW  - microRNA
KW  - neuropathic pain
KW  - blood nerve barrier
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318226
VL  - 1515
IS  - 1
SP  - 184
EP  - 195
ER  - 
TY  - JOUR
A1  - Kindl, Gudrun
A1  - Teichmüller, Karolin
A1  - Escolano-Lozano, Fabiola
A1  - Birklein, Frank
A1  - Rittner, Heike L.
T1  - Pain, disability, and lifestyle: Patients with complex regional pain syndrome compared to chronic musculoskeletal pain-A retrospective analysis
JF  - European Journal of Pain
N2  - Background
Complex regional pain syndrome (CRPS) is an orphan disease occurring as a complication after trauma. Due to its acute onset and the typical clinical presentation of the inflammatory and autonomous signs, it is an eye-catching chronic pain disease affecting also young and working people. In social media and the internet, high pain severity and the unfavourable prognosis are often empathized.
Methods
Here, we compared epidemiological, pain and lifestyle factors of 223 CPRS patients from the “ncRNAPain” cohort with 255 patients with chronic musculoskeletal pain (MSK). MSK patients were recruited at the beginning of a multimodal pain therapy programme. We searched for factors predicting pain intensity.
Results
Both chronic pain diseases affected women in middle age. Patients with MSK were more obese, drank more alcohol, and were less educated (Pearson chi-square Test or Mann–Whitney/U-Test). Both groups smoked more than healthy people in the OECD (Organization for Economic Cooperation and Development). Mann–Whitney/U-Test confirmed that CRPS patients did not have more severe pain and did not suffer more from pain-related disability than patients with MSK. CRPS patients also had less psychiatric comorbidities. Multiple linear regression analysis revealed that group assignment, depressive characteristics, body mass index, average alcohol consumption and smoking predicted higher pain ratings, while disease duration, anxiety symptoms or gender had no influence on pain intensity.
Conclusion
In summary, our study supports a more optimistic view on pain in CRPS patients in comparison to MSK and identifies lifestyle factors that might contribute to the pathophysiology like smoking and drinking. Important next steps are the identification of CRPS patients at risk for chronification or—vice versa—with protective factors for pain resolution.
Significance
This study compares complex regional pain syndrome (CRPS) and chronic musculoskeletal pain and questions previously reported pain, disability and lifestyle factors associated with CRPS.
KW  - complex regional pain syndrome
KW  - chronic musculoskeletal pain
KW  - comparison
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318200
VL  - 26
IS  - 3
SP  - 719
EP  - 728
ER  -