Visualisation of tissue kallikrein, kininogen and kinin receptors in human skin following trauma and in dermal diseases

During dermal injury and inflammation the serine proteases kallikreins cleave endogenous, multifunctional substrates (kininogens) to form bradykinin and kallidin. The actions of kinins are mediated by preferential binding to constitutively expressed kinin-B2 receptors or inducible kinin-B1 receptors. A feature of the kinin-B1 receptors is that they show low levels of expression, but are distinctly upregulated following tissue injury and inflammation. Because recent evidence suggested that kinin-B1 receptors may perform a protective role during inflammation, we investigated the specific occurrence of the kallikrein-kinin components in skin biopsies obtained from normal skin, patients undergoing surgery, basalioma, lichenificated atopic eczema, and psoriasis. The tissue was immunolabelled in order to determine the localisation of tissue pro-kallikrein, kallikrein, kininogen and kinin receptors. The kinin components were visualised in normal, diseased and traumatised skin, except that no labelling was observed for kininogen in normal skin. Of the five types of tissue examined, upregulation of kinin-B1 receptors was observed only in skin biopsies obtained following surgery. In essence, the expression of kinin-B1 receptors did not appear to be enhanced in the other biopsies. Within the multiple steps of the inflammatory cascade in wound healing, our results suggest an important regulatory role for kinin-B1 receptors during the first phase of inflammation following injury

Perineural mast cells are specifically enriched in pancreatic neuritis and neuropathic pain in pancreatic cancer and chronic pancreatitis.

BACKGROUND: Pancreatic neuritis is a histopathological hallmark of pancreatic neuropathy and correlates to abdominal neuropathic pain sensation in pancreatic adenocarcinoma (PCa) and chronic pancreatitis (CP). However, inflammatory cell subtypes that compose pancreatic neuritis and their correlation to the neuropathic pain syndrome in PCa and CP are yet unknown. METHODS: Inflammatory cells within pancreatic neuritis lesions of patients with PCa (n = 20) and CP (n = 20) were immunolabeled and colorimetrically quantified with the pan-leukocyte marker CD45, with CD68 (macrophages), CD8 (cytotoxic T-lymphocytes), CD4 (T-helper cells), CD20 (B-lymphocytes), NCL-PC (plasma cells), neutrophil elastase, PRG2 (eosinophils), anti-mast cell (MC) tryptase and correlated to pain sensation. Perineural mast cell subtypes were analyzed by double immunolabeling with MC chymase. Expression and neural immunoreactivity of protease-activated receptor type 1 (PAR-1) and type 2 (PAR-2) were analyzed in PCa and CP and correlated to pain status of the patients. RESULTS: In PCa and CP, nerves were predominantly infiltrated by cytotoxic T-lymphocytes (PCa: 35% of all perineural inflammatory cells, CP: 33%), macrophages (PCa: 39%, CP: 33%) and MC (PCa: 21%, CP: 27%). In both entities, neuropathic pain sensation was associated with a specific increase of perineural MC (PCa without pain: 14% vs. PCa with pain: 31%; CP without pain: 19% vs. CP with pain: 34%), not affecting the frequency of other inflammatory cell subtypes. The vast majority of these MC contained MC chymase. PAR-1 and PAR-2 expression did not correlate to the pain sensation of PCa and CP patients. CONCLUSION: Pancreatic neuritis in PC and CP is composed of cytotoxic T-lymphocytes, macrophages and MC. The specific enrichment of MC around intrapancreatic nerves in neuropathic pain due to PCa and CP suggests the presence of MC-induced visceral hypersensitivity in the pancreas. Therefore, pancreatic and enteric neuropathies seem to share a similar type of neuro-immune interaction in the generation of visceral pain

Protease-activated-receptor (PAR) type 1 (PAR-1) and type 2 (PAR-2) in human pancreatic cancer (PCa) and chronic pancreatitis (CP).

<p>(A) Expression of PAR-1 and PAR-2 was compared between normal human pancreas (NP), CP and PCa tissues via qRT-PCR and did not differ between these three entities. Expression was normalized first to the housekeeping gene cyclophilin B and then to NP. (B) In PCa, the tissue levels of PAR-1 and PAR-2 did not differ between patients with pain versus patients without pain. (C) Similarly, also in CP, there was no difference in the tissue mRNA levels of PAR-1 and PAR-2 in patients with no pain versus with pain. (D) Intrapancreatic nerves in PCa were analyzed for the immunoreactivity for PAR-1 and PAR-2 and correlated to the pain status of patients. Here, pain sensation was not associated with differences in the immunoreactivity of intrapancreatic nerves for PAR-1 or PAR-2. (E) In analogy with PCa, also in CP, patients with pain exhibited similar immunoreactivities in nerves for PAR-1 and PAR-2 as patients without pain.</p

Analysis of mast cell (MC) phenotype in NP, PCa and CP.

<p>(A) Human pancreatic tissue samples from NP, PCa and CP were double-immunolabeled for perineural MC-tryptase (red) and MC-chymase (green). In all three entities, the vast majority of perineural MC demonstrated double immunoreactivity (yellow in overlay) for MC-tryptase and -chymase. In CP, there were significantly greater relative amounts of double-immunoreactive MC among patients with pain than among those without pain. The white scale bars indicate 100 µm. (B) In accordance with increased perineural MC-tryptase in painful PCa and CP, the perineural MC chymase immunoreactivity was significantly greater among PCa and CP patients with pain than in patients without pain. Results are expressed as median (Minimum; Maximum).</p