Effects of sensory denervation by neonatal capsaicin administration on experimental pancreatitis induced by dibutyltin dichloride

Botanical drugs and their natural compounds: a neglected treasury for inhibiting the carcinogenesis of pancreatic ductal adenocarcinoma

CONTEXT

Pancreatic ductal adenocarcinoma (PDAC), which is characterized by its malignant nature, presents challenges for early detection and is associated with a poor prognosis. Any strategy that can interfere with the beginning or earlier stage of PDAC greatly delays disease progression. In response to this intractable problem, the exploration of new drugs is critical to reduce the incidence of PDAC.

OBJECTIVE

In this study, we summarize the mechanisms of pancreatitis-induced PDAC and traditional Chinese medicine (TCM) theory and review the roles and mechanisms of botanical drugs and their natural compounds that can inhibit the process of pancreatitis-induced PDAC.

METHODS

With the keywords 'chronic pancreatitis', 'TCM', 'Chinese medicinal formulae', 'natural compounds', 'PDAC' and 'pancreatic cancer', we conducted an extensive literature search of the PubMed, Web of Science, and other databases to identify studies that effectively prevent PDAC in complex inflammatory microenvironments.

RESULTS

We summarized the mechanism of pancreatitis-induced PDAC. Persistent inflammatory microenvironments cause multiple changes in the pancreas itself, including tissue damage, abnormal cell differentiation, and even gene mutation. According to TCM, pancreatitis-induced PDAC is the process of 'dampness-heat obstructing the spleen and deficiency due to stagnation' induced by a variety of pathological factors. A variety of botanical drugs and their natural compounds, such as Chaihu classical formulae, flavonoids, phenolics, terpenoids, etc., may be potential drugs to interfere with the development of PDAC via reshaping the inflammatory microenvironment by improving tissue injury and pancreatic fibrosis.

CONCLUSIONS

Botanical drugs and their natural compounds show great potential for preventing PDAC in complex inflammatory microenvironments.

Morphological and immunohistochemical comparison of intrapancreatic nerves between chronic pancreatitis and type 1 autoimmune pancreatitis

OBJECTIVES

The abdominal pain associated with chronic pancreatitis (CP) may be related to the increased number and size of intrapancreatic nerves. On the other hand, patients with type 1 autoimmune pancreatitis (AIP) rarely suffer from the pain syndrome, and there are no previous studies concerning the histopathological findings of intrapancreatic nerves in patients with type 1 AIP. The current study is aimed at investigating the differences in the histopathological and immunohistochemical findings of intrapancreatic nerves in patients with CP and type 1 AIP.

METHODS

Neuroanatomical differences between CP and type 1 AIP were assessed by immunostaining with a pan-neuronal marker, protein gene product 9.5 (PGP9.5). The number (neural density) and area (neural hypertrophy) of PGP9.5-immunopositive nerves were quantitatively analyzed. Furthermore, the expression of nerve growth factor (NGF), and a high affinity receptor for NGF, tyrosine kinase receptor A (TrkA), was assessed by immunohistochemistry.

RESULTS

Both neural density and hypertrophy were significantly greater in pancreatic tissue samples from patients with CP than those with normal pancreas or type 1 AIP. NGF expression was stronger in type 1 AIP than in CP, whereas TrkA expression in type 1 AIP was poorer than in CP.

CONCLUSIONS

Although CP and type 1 AIP are both characterized by the presence of sustained pancreatic inflammation, they are different in terms of the density and hypertrophy of intrapancreatic nerve fibers. It is possible that this may be related to the difference in the activity of the NGF/TrkA-pathway between the two types of pancreatitis.

Sensory nerves and pancreatitis

Sensory nerves are a kind of nerve that conduct afferent impulses from the periphery receptors to the central nervous system (CNS) and are able to release neuromediators from the activated peripheral endings. Sensory nerves are particularly important for microcirculatory response, and stimulation of pancreatic sensory nerves releases a variety of neuropeptides such as substance P (SP), calcitonin gene-related peptide (CGRP), etc., leading to neurogenic inflammation characterized as the local vasodilatation and plasma extravasation. Deactivation of sensory nerves often leads to the disturbances of pancreatic microcirculation. Pancreatitis is a common digestive disease that can lead to severe complications and even death if it goes untreated. Experimental studies in animals and tissue analysis in patients with pancreatitis have shown significant changes in sensory nerves supplying the pancreatic gland. Thus making clear the whole mechanism of pancreatitis is essential to treat and cure it. Sensory nerves may have a close correlation with the development of pancreatitis, and knowing more about the role of sensory nerve in pancreatitis is important for the treatment for pancreatitis. This review is aimed to summarize the relationship between sensory nerves and pancreatitis.

Beneficial Effect of Low-Fat Elemental Diet Therapy on Pain in Chronic Pancreatitis

Background & Aims. Chronic pancreatitis (CP) is often associated with abdominal pain, which impairs quality of life. The aim of this prospective study was to clarify whether the use of a low-fat elemental diet (ED) is beneficial for managing pain in patients with CP. Methods. Seventeen CP patients with pain despite fat-restricted dietary and conventional medical treatments were enrolled in this prospective study. These patients received low-fat ED therapy in addition to restricting fat intake for 8 weeks. The change of pain severity was examined by interviewing the patient and status of analgesic use. Results. Mean serum levels of amylase and lipase at 8 weeks after the beginning of low-fat ED therapy decreased compared to those before the therapy. At 8 weeks, pain alleviation after low-fat ED therapy was reported in 15 out of 17 patients (88%). Of these 15 patients, 10 patients reported complete pain disappearance. One of 3 patients with severe or moderate pain requiring analgesic was relieved of analgesic use after low-fat ED therapy. Conclusion. Low-fat ED therapy is useful as means of pain control in CP. The therapy is recommended in outpatients with CP who present with pain despite conventional dietary and medical treatments.

Capsaicin reduces tissue damage in experimental acute pancreatitis

OBJECTIVES

Calcitonin gene-related peptide (CGRP) is released from perivascular pancreatic nerves. It effects vasomotion and cytokine liberation in inflammatory processes, including acute pancreatitis (AP). Calcitonin gene-related peptide liberation is stimulated by capsaicin, a substance of red hot chili peppers. Aim of the study was to investigate the influence of exogenous capsaicin on experimental AP.

METHODS

Acute pancreatitis was induced in rats by glycodeoxycholic acid and cerulein. Animals were divided into 4 groups: (1) severe AP, (2) severe AP+capsaicin, (3) control without AP, and (4) control+capsaicin. After 24 hours, survival, histology, and CGRP were evaluated (n=6/group). In additional animals, erythrocyte flow and leukocyte activation were evaluated by intravital microscopy 6 hours after AP induction (n=6/group).

RESULTS

In the control groups, all animals survived without histological alterations. Mortality in severe AP was 67%. Capsaicin reduced mortality to 16% (P<0.05). Acute pancreatitis animals developed pancreatic inflammation and necrosis, which was significantly less after capsaicin application. Intravital microscopy in severe AP showed reduced erythrocyte velocity and increased leukocyte adhesion, which was nearly normalized by capsaicin (P<0.01). Calcitonin gene-related peptide increased in both capsaicin groups, indicating endogenous CGRP liberation (P<0.01).

CONCLUSION

Capsaicin releases endogenous CGRP with improved pancreatic microcirculation and reduced inflammation in experimental AP. This underlines neuropeptide activity in the pathogenesis of AP.