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IntroductionAccumulating evidence suggests an important role for interleukin 17 (IL-17) in the pathogenesis of several inflammatory diseases, including rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Accordingly, clinical trials aimed at blocking IL-17 have been initiated, but clinical results between patients and across different diseases have been highly variable. The objective was to determine the variability in expression of IL-17A, IL-17F and their receptors IL-17RA and IL-17RC in the synovia of patients with arthritis.MethodsSynovial biopsies were obtained from patients with RA (n = 11), PsA (n = 15) and inflammatory osteoarthritis (OA, n = 14). For comparison, synovia from noninflamed knee joints (n = 7) obtained from controls were included. Frozen sections were stained for IL-17A, IL-17F, IL-17RA and IL-17RC and evaluated by digital image analysis. We used confocal microscopy to determine which cells in the synovium express IL-17A and IL-17F, double-staining with CD4, CD8, CD15, CD68, CD163, CD31, von Willebrand factor, peripheral lymph node address in, lymphatic vessel endothelial hyaluronan receptor 1, mast cell tryptase and retinoic acid receptor–related orphan receptor γt (RORγt).ResultsIL-17A, IL-17F, IL-17RA and IL-17RC were abundantly expressed in synovial tissues of all patient groups. Whereas IL-17RA was present mostly in the synovial sublining, IL-17RC was abundantly expressed in the intimal lining layer. Digital image analysis showed a significant (P < 0.05) increase of only IL-17A in arthritis patients compared to noninflamed control tissues. The expression of IL-17A, IL-17F and their receptors was similar in the different patient groups, but highly variable between individual patients. CD4+ and CD8+ cells coexpressed IL-17A, and few cells coexpressed IL-17F. IL-17A and IL-17F were not expressed by CD15+ neutrophils. Mast cells were only occasionally positive for IL-17A or IL-17F. Interestingly, IL-17A and IL-17F staining was also observed in macrophages, as well as in blood vessels and lymphatics. This staining probably reflects receptor-bound cytokine staining. Many infiltrated cells were positive for the transcription factor RORγt. Colocalisation between RORγt and IL-17A and IL-17F indicates local IL-17 production.ConclusionsIncreased expression of IL-17A is not restricted to synovial tissues of RA and PsA patients; it is also observed in inflammatory OA. The heterogeneous expression levels may explain nonresponse to anti-IL-17 therapy in subsets of patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-014-0426-z) contains supplementary material, which is available to authorized users.

Irritable bowel syndrome is in part characterized by an increased sensitivity to colonic distension. Stress is an important trigger factor for symptom generation. We hypothesized that stress induces visceral hypersensitivity via mast cell degranulation and transient receptor ion channel 1 (TRPV1) modulation. We used the rat model of neonatal maternal separation (MS) to investigate this hypothesis. The visceromotor response to colonic distention was assessed in adult MS and non-handled (NH) rats before and after acute water avoidance (WA) stress. We evaluated the effect of the mast cell stabilizer doxantrazole, neutralizing antiserum against the mast cell mediator nerve growth factor (NGF) and two different TRPV1 antagonists; capsazepine (non-specific) and SB-705498 (TRPV1-specific). Immunohistochemistry was used to assess post-WA TRPV1 expression in dorsal root ganglia and the presence of immunocytes in proximal and distal colon. Retrograde labelled and microdissected dorsal root ganglia sensory neurons were used to evaluate TRPV1 gene transcription. Results showed that acute stress induces colonic hypersensitivity in MS but not in NH rats. Hypersensitivity was prevented by prestress administration of doxantrazole and anti-NGF. Capsazepine inhibited and SB-705498 reversed poststress hypersensitivity. In MS rats, acute stress induced a slight increase in colonic mast cell numbers without further signs of inflammation. Post-WA TRPV1 transcription and expression was not higher in MS than NH rats. In conclusion, the present data on stress-induced visceral hypersensitivity confirm earlier reports on the essential role of mast cells and NGF. Moreover, the results also suggest that TRPV1 modulation (in the absence of overt inflammation) is involved in this response. Thus, mast cells and TRPV1 are potential targets to treat stress-induced visceral hypersensitivity.

The aim of this study was twofold, that is the generation of a reliable model for skin barrier disruption and repair and to evaluate recovery of damaged skin after application of vernix caseosa (VC). VC was selected as its wound healing properties were suggested previously, but never clearly demonstrated. Five different levels of barrier disruption in mice, accomplished by tape-stripping, were evaluated. Disruption models such as moderate, severe #1 and #2 (transepidermal water loss (TEWL) of 31 ± 2, 59 ± 4 and 66 ± 3 g ⁄ m 2 ⁄ h, respectively) showed complete recovery within 72 h. However, not all corneocytes were removed after tape-stripping. Additionally, models such as severe #3 and #4 (TEWL of 73 ± 5 and 79 ± 6 g ⁄ m 2 ⁄ h, respectively) with a more severe disruption were evaluated. After tape-stripping, all corneocytes were removed and the remaining epidermis was intact. However, model #3 still showed complete recovery within 72 h. With model #4, a crust was formed and almost complete recovery (approximately 90%) was obtained within only 8 days. The effect of VC application on recovery of disrupted skin was evaluated with model #3 and #4. Model #3 showed that application of VC predominantly influenced initial recovery and is therefore merely appropriate to study the effect of formulations in the initial recovery period. Topical application of VC on model #4 considerably increased initial and long-term recovery. Moreover, VC application promoted rapid formation of stratum corneum and prevented epidermal thickening. These observations not only confirm the ability of VC to enhance barrier recovery, but also suggest potential use of this treatment clinically.Key words: skin barrier recovery -tape-stripping -vernix caseosaPlease cite this paper as: Development of a murine model to evaluate the effect of vernix caseosa on skin barrier recovery.