Expression of Smad7 and Smad ubiquitin regulatory factor 2 in a rat model of chronic pancreatitis

Methods of a New Chronic Pancreatitis and Spontaneous Pancreatic Cancer Mouse Model Using Retrograde Pancreatic Duct Injection of Dibutyltin Dichloride

The current study aimed to develop a new chronic pancreatitis and spontaneous pancreatic cancer model on C57/BL6 mouse through retrograde pancreatic duct injection of dibutyltin dichloride (DBTC) and explore its basic pathological changes as compared to the previous published chronic pancreatitis model through tail vein injection of DBTC with alcohol drinking. C57/BL6 mice were randomly divided into 3 groups: CG (control group; n = 15), VG (tail vein injection of DBTC (8 mg/kg) with 10% alcohol drinking group; n = 20), and PG (retrograde pancreatic duct injection of DBTC group (1 mg/kg); n = 30). Five mice in each group were sacrificed at a specific time point after the first treatment. The pathological section was observed. The activities of amylase, bilirubin, and hyaluronic acid in serum were determined. The expression of fibronectin, COL1A1, α-SMA, MMP-1, and TIMP-1 in the pancreas was assayed. Severe fibrosis of the pancreas with inflammatory cell infiltration could be observed on day 21 in the PG. In the VG, slight fibrosis of the pancreas with inflammatory cell infiltration was observed on day 28. There were significant differences in serum amylase, bilirubin, and hyaluronic acid levels between the PG and VG. The protein level of COL1A1 and α-SMA significantly increased in the PG. The mRNA expression of TIMP-1 is upregulated and the MMP-1 mRNA level is downregulated in the PG. Finally, typical neoplastic pathological change is significantly obvious in the PG. In conclusion, we established and validated a new chronic pancreatitis (CP) and spontaneous pancreatic cancer mouse model through retrograde injection of DBTC into the pancreatic duct. Previously reported mouse model through tail vein injection of DBTC with alcohol drinking could not cause obvious CP and neoplastic pathological change in mice.

Prospect and clinical value of oxymatrine in prevention and treatment of pancreatic fibrosis

Studies have confirmed that pancreatic stellate cell activation is the central event in the initiation and development of pancreatic fibrosis (PF), but the specific mechanism of PF is still unknown, and there is no specific treatment for PF. Some basic studies have confirmed that oxymatrine (OMT) has a certain therapeutic effect on PF, but further research is needed. It can be predicted that OMT has a far-reaching research prospect and good clinical application value for the prevention and treatment of PF, and is also conducive to the better development and utilization of traditional Chinese herbal medicine radix sophorae flavescentis.

HDAC inhibitors promote pancreatic stellate cell apoptosis and relieve pancreatic fibrosis by upregulating miR-15/16 in chronic pancreatitis

In chronic pancreatitis, PSCs are activated by proinflammatory cytokines to induce pancreatic fibrogenesis. HDAC inhibition protected against the pancreatic fibrosis and the apoptosis of PSCs through induced apoptosis and depressed inflammation. In our study, we found that miR-15 and miR-16 decreased significantly in chronic pancreatitis and HDAC inhibition could recover the levels of these two miRNAs. HDAC regulated the transcription of miR-15 and miR-16, which then modulate the apoptosis and fibrosis of PSCs. And we proved that Bcl-2 and Smad5 were the target genes of miR-15 and miR-16, which illustrated how HDAC inhibition alleviated the apoptosis and fibrogenesis of PSCs in chronic pancreatitis. These results suggested that HDAC inhibition protects against CP by promoting apoptosis and TGF-β/Smads signaling pathways, and indicated that HDAC inhibition is a potential therapy to alleviate CP patients in clinic, and these need to be explored further.

SPOP inhibits mice pancreatic stellate cell activation by promoting FADD degradation in cerulein-induced chronic pancreatitis

Pancreatic stellate cells (PSCs) have been recognized as key mediators of pancreatic fibrosis, a characteristic feature of chronic pancreatitis (CP). As a cullin-based E3 ubiquitin ligase, speckle-type POZ protein (SPOP) has been identified to participate in tumorigenesis and organ development. However, its biological role in CP remains unknown. Therefore, this study sought to investigate the changed expression of SPOP in CP and to examine the effect on mice PSCs activation of SPOP. We found that SPOP was downregulated in the pancreatic tissues of cerulein-induced CP mice. siRNA-mediated knockdown of SPOP led to significant promotion in primary PSCs activity by activating the nuclear factor-kappaB (NF-κB)/interleukin-6 (IL-6) signaling pathway. In addition, we examined the effects of Fas-associated death domain (FADD), a proven SPOP substrate that activates NF-κB, on the regulation of PSCs activation. We found that FADD was downregulated by SPOP via interaction-mediated degradation, and was upregulated during PSCs activation. The promotion of PSCs activation in knocking down SPOP with siSPOP-1 were counteracted by knocking down FADD. The results suggest that the SPOP-induced inhibition of PSCs activation partially depended on FADD. These results highlight the importance of SPOP in CP and provide a potential target for therapeutic intervention.

Large mesenteric hematoma after extracorporeal shock wave lithotripsy for pancreatic stones: A case report

RATIONALE

Mesenteric hematoma after extracorporeal shock wave lithotripsy (ESWL) for pancreatic stones is a very rare complication which has never been reported before.

PRESENTING CONCERNS

We reported a case of a 36-year-old male diagnosed as chronic pancreatitis with pancreatic stones and a large pancreatic pseudocyst. He underwent 3 repeated sessions of pancreatic ESWL (P-ESWL). After the last session of P-ESWL, he complained of dizziness. Physical examination revealed a large mass in the right abdomen.

DIAGNOSIS

Emergent upper abdominal computerized tomography (CT) revealed this mass is a mesenteric hematoma with the size of 8.2 cm × 11.7 cm in the right abdominal cavity after P-ESWL and there was no sign of intestinal obstruction.

INTERVENTIONS

With close monitoring of vital signs, the patient received conservative treatment for several days. Dynamic abdominal ultrasound monitoring revealed the mesenteric hematoma had organized.

OUTCOMES

Vital signs of the patient were stable after fluid transfusion. Three-month follow-up CT showed the mesenteric hematoma had absorbed completely.

LESSONS

Mesenteric hematoma rarely occurs after P-ESWL and it alerts us the importance of considering uncommon complications after P-ESWL. If mesenteric hematoma occurs after P-ESWL, conservative treatment could be the first choice while surgery can also be considered.

Effects of the tumor suppressor PTEN on biological behaviors of activated pancreatic stellate cells in pancreatic fibrosis

Pancreatic stellate cells (PSCs), when activated, are characterized by proliferation and collagen synthesis, and contribute to extracellular matrix deposition in pancreatic fibrosis. Concomitantly, fibrosis is linked with the loss of PTEN (phosphatase and tensin homolog) protein in several organs. This study investigated the association between PTEN protein levels and the activated or apoptotic status of PSCs in a rat model of chronic pancreatitis. In addition, the activation status and biological behaviors of culture-activated PSCs were analyzed after lentiviral transfection with wildtype or mutant (G129E) PTEN for upregulation, or PTEN short hairpin RNA for downregulation, of PTEN. In vivo, PTEN levels gradually decreased during pancreatic fibrosis, which positively correlated with apoptosis of activated PSCs, but negatively with PSC activation. In vitro, activated PSCs with wildtype PTEN showed less proliferation, migration, and collagen synthesis compared with control PSCs, and greater numbers were apoptotic; activated PSCs with mutant PTEN showed similar, but weaker, effects. Furthermore, AKT and FAK/ERK signaling was involved in this process. In summary, activated PSCs during pancreatic fibrosis in vivo have lower levels of PTEN. In vitro, PTEN appears to prevent PSCs from further activation and promotes apoptosis through regulation of the AKT and FAK/ERK pathways.

P2X7R Blockade Prevents NLRP3 Inflammasome Activation and Pancreatic Fibrosis in a Mouse Model of Chronic Pancreatitis

OBJECTIVES

The aim of this study was to investigate the role of P2X7R (purinergic 2X7 receptor) and NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome activation in the process of pancreatic fibrosis in a mouse model of chronic pancreatitis (CP).

METHODS

Chronic pancreatitis was induced by repeated intraperitoneal injections of 50 μg/kg cerulein for 6 weeks in mice. P2X7R antagonist oxidized ATP (OxATP) or brilliant blue G (BBG) was administered after the last cerulein injection for 2 weeks. Pancreatic chronic inflammation and fibrosis were evaluated by histological score, Sirius red staining, and alpha-smooth muscle actin immunohistochemical staining. We further determined pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, interleukin 1β (IL-1β), and IL-18.

RESULTS

The pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, IL-1β, and IL-18 were all reduced significantly in both the OxATP and BBG groups (P < 0.05). The pancreatic chronic inflammation and the fibrosis indices were all remarkably attenuated (P < 0.05).

CONCLUSIONS

P2X7R antagonist OxATP and BBG significantly decreased pancreatic chronic inflammation and fibrosis in a mouse CP model and suggested that blockade of P2X7R-NLRP3 inflammasome signaling pathway may represent a novel therapeutic strategy for CP and its fibrotic process.

Computed tomography for diagnosis of early chronic pancreatitis in a rat model

AIM: To assess the value of computed tomography (CT) in the diagnosis of early chronic pancreatitis (CP) in a rat model.

METHODS: A rat model of chronic pancreatitis was established by injection of dibutyltin dichloride (DBTC), and control rats were treated with equal volume of physiological saline. The animals were sacrificed 7 d, 14 d, and 28 d after injection. Abdominal CT scans were performed in all rats, and serum amylase (AMY), lipase (LIPA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL) and fasting blood glucose were detected. Histopathology of rat pancreas was assessed by HE staining.

RESULTS: Serum ALT and TBIL increased in both early and late stages of CP. CT scans revealed that there was a significant difference in rat pancreatic histopathology by HE staining among 7 d, 14 d, and 28 d after injection of DBTC.

CONCLUSION: CT imaging characteristics of early CP are very important for the early diagnosis and treatment of this disease.

Transglutaminase 2 has opposing roles in the regulation of cellular functions as well as cell growth and death

Transglutaminase 2 (TG2) is primarily known as the most ubiquitously expressed member of the transglutaminase family with Ca²⁺-dependent protein crosslinking activity; however, this enzyme exhibits multiple additional functions through GTPase, cell adhesion, protein disulfide isomerase, kinase, and scaffold activities and is associated with cell growth, differentiation, and apoptosis. TG2 is found in the extracellular matrix, plasma membrane, cytosol, mitochondria, recycling endosomes, and nucleus, and its subcellular localization is an important determinant of its function. Depending upon the cell type and stimuli, TG2 changes its subcellular localization and biological activities, playing both anti- and pro-apoptotic roles. Increasing evidence indicates that the GTP-bound form of the enzyme (in its closed form) protects cells from apoptosis but that the transamidation activity of TG2 (in its open form) participates in both facilitating and inhibiting apoptosis. A difficulty in the study and understanding of this enigmatic protein is that opposing effects have been reported regarding its roles in the same physiological and/or pathological systems. These include neuroprotective or neurodegenerative effects, hepatic cell growth-promoting or hepatic cell death-inducing effects, exacerbating or having no effect on liver fibrosis, and anti- and pro-apoptotic effects on cancer cells. The reasons for these discrepancies have been ascribed to TG2's multifunctional activities, genetic variants, conformational changes induced by the immediate environment, and differences in the genetic background of the mice used in each of the experiments. In this article, we first report that TG2 has opposing roles like the protagonist in the novel Dr. Jekyll and Mr. Hyde, followed by a summary of the controversies reported, and finally discuss the possible reasons for these discrepancies.