Increased Occurrence of Nerve Fibres and some Neuropeptides in Subacromial Tissue Biopsies from Patients with Impingement Syndrome of the Shoulder
(English)Manuscript (preprint) (Other academic)
Background: The pathophysiology of subacromial inflammation is not fully understood. In the present study we evaluate the presence of sensory and sympathetic nerve fibres and some neuropeptides in biopsies from the supraspinatus tendon and the subacromial bursa of patients with chronic subacromial inflammation as well as of control cases.
Methods: The occurrence of nerve fibres was subjectively assessed by immunohistochemistry. The concentration of substance P (SP), calcitonin generelated peptide (CGRP) and neuropeptide Y (NPY) was measured by radioimmunoassay (RIA).
Results: In tendon biopsies from patients with an intact or partially ruptured tendon protein gene product 9.5-like immunoreactive (LI), SP-LI and CGRP-LI nerve fibres were abnormally abundant. In patients with a total tendon rupture nerve fibre occurrence was normal. All biopsies from the bursa exhibited an abnormally high occurrence of SP- and CGRP-LI nerve fibres. In all biopsies the tendon and the bursa contained more blood vessels than normal. The vessels were surrounded by NPY- and tyrosine hydroxylase-LI nerve fibres in a subjectively normal pattern. RIA analysis revealed that the concentration of all three neuropeptides was abnormally high in tendon biopsies from patients with an intact or partially ruptured tendon. Tendon biopsies from patients with total tendon rupture showed statistically normal levels. Biopsies from the bursa showed abnormally high levels of SP and CGRP but normal levels of NPY in all patients.
Conclusion: We conclude, that the supraspinatus tendon and the subacromial bursa exhibit an increased occurrence of nerve fibres and some neuropeptides in patients with chronic subacromial inflammation.
Clinical relevance: Patients with chronic subacromial inflammation have a disabling pain problem. The increased local occurrence of sensory andsympathetic axons in the inflamed tissues as well as the elevated tissue concentration of certain neuropeptides may represent important factors behind that problem.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-80036OAI: oai:DiVA.org:liu-80036DiVA: diva2:545109