Detection of pancreatic fibrosis using magnetic resonance imaging: correlation with histopathology

Background and Hypothesis: Diagnosis of chronic pancreatitis (CP) is challenging and controversial. Magnetic Resonance Imaging (MRI) offers a noninvasive modality to diagnose CP, but its findings have been rarely correlated with histopathology. We aimed to assess the correlation of T1 signal intensity ratio of pancreas to spleen (T1 SIRp/s) and arterio-venous ratio (AVR) of the parenchyma on MRI and Cambridge score on MRCP with surgical histopathology in patients who underwent pancreatic resection. Methods: We identified 160 pancreatic resections performed in adults between 2017 and 2019 by searching our institution’s surgery database. Seventy-one of them had surgical pathology specimens available and 59 of them had MRI/MRCP within 3 months prior to the surgery. Histologic grading was performed by a gastrointestinal pathologist using Ammann’s fibrosis score. Two image analysts blinded to the clinical information and fibrosis score measured T1 SIRp/s from unenhanced T1-weighted fat-saturated gradient-echo images and arterio-venous ratio (AVR) from post-contrast dynamic phase. Cambridge score was also recorded from MRCP. Statistical analysis included Pearson’s correlation coefficient of the T1 SIRp/s, AVR, and Cambridge score with the fibrosis score and weighted kappa for interobserver agreement. Results: Correlations between T1 SIRp/s and AVR with the fibrosis score were (r= -0.30, p=0.02, 95%CI: -0.51 to -0.04 and r= -0.36, p=0.01, 95%CI: -0.58 to -0.09, respectively). In comparison, there is less correlation between the Cambridge grade and the fibrosis (r= 0.17, p=0.15, 95% CI for r= -0.07 to 0.39). Interobserver agreement was good (kappa=0.80). Conclusion: There is moderate correlation between the T1 signal intensity and enhancement ratio of the pancreas with pancreatic fibrosis. This is higher than the correlation between the Cambridge grade and fibrosis. Multi-institutional, prospective studies are needed to verify T1 SIR and AVR as potential imaging biomarkers of pancreatic fibrosis.

Association between pancreatic fibrosis and development of pancreoprivic diabetes after pancreaticoduodenectomy

This study investigated the correlation between pancreatic fibrosis (PF) and development of pancreoprivic diabetes after pancreaticoduodenectomy (PD). Ninety-five patients who underwent PD at Gangnam Severance Hospital between 2014 and 2017 were enrolled. PF grade was evaluated with alpha-smooth muscle actin (SMA) and Masson’s trichrome (TRC) staining. New-onset pancreoprivic diabetes and recurrence of disease were evaluated using fasting blood glucose measurement and radiography taken at 3-month intervals. Sixty-one patients did not have preoperative diabetes, however, 40 (65.6%) patients developed pancreoprivic diabetes after PD. High-grade PF was more common in the diabetes group than in the normal group (SMA, 42.5% vs. 28.6%, P = 0.747; TRC, 47.5% vs. 28.6%, P = 0.361). The 1-year cumulative incidence of hyperglycemia/pancreoprivic diabetes was higher with high-grade PF than low-grade PF (SMA, 94.4% vs. 73.0%, P = 0.027; TRC, 89.3% vs. 75.0%, P = 0.074). The SMA-TRC combined high-grade group had a higher proportion of primary pancreatic disease than the combined low-grade group (90.0% vs. 37.5%, P = 0.001). The 5-year disease-free survival of patients with pancreatic cancer was worse with high-grade PF than low-grade PF (SMA, 24.5% vs. 66.3%, P = 0.026; TRC, 23.6% vs. 58.4%, P = 0.047). In conclusion, patients with severe PF are more likely to develop pancreoprivic diabetes after PD and have worse disease-free survival.

Lnc-PFAR facilitates autophagy and exacerbates pancreatic fibrosis by reducing pre-miR-141 maturation in chronic pancreatitis

Chronic pancreatitis (CP) is described as progressive inflammatory fibrosis of pancreas, accompanied with irreversible impaired endocrine and exocrine insufficiency. Pancreatic stellate cells (PSCs) are widely distributed in the stroma of the pancreas and PSCs activation has been shown as one of the leading causes for pancreatic fibrosis. Our previous study has revealed that autophagy is dramatically activated in CP tissues, which facilitates PSCs activation and pancreatic fibrosis. Long non-coding RNAs (LncRNAs) have been recognized as crucial regulators for fibrosis-related diseases. LncRNAs interact with RNA binding protein or construct competitive endogenous RNA (ceRNA) hypothesis which elicited the fibrotic processes. Until now, the effects of lncRNAs on PSCs activation and pancreatic fibrosis have not been clearly explored. In this study, a novel lncRNA named Lnc-PFAR was found highly expressed in mouse and human CP tissues. Our data revealed that Lnc-PFAR facilitates PSCs activation and pancreatic fibrosis via RB1CC1-induced autophagy. Lnc-PFAR reduces miR-141 expression by suppressing pre-miR-141 maturation, which eventually upregulates the RB1CC1 and fibrosis-related indicators expression. Meanwhile, Lnc-PFAR enhanced PSCs activation and pancreatic fibrosis through trigging autophagy. Our study interrogates a novel lncRNA-induced mechanism in promoting the development of pancreatic fibrosis, and Lnc-PFAR is suggested to be a prospective therapeutic target in clinical scenarios.

Activated Pancreatic Stellate Cells Promote Acinar Duct Metaplasia by Disrupting Mitochondrial Respiration and Releasing Reactive Oxygen Species

Background: Chronic pancreatitis (CP) is a long-term risk factor for pancreatic ductal adenocarcinoma (PDAC), and both diseases share a common etiology. The activation of Pancreatic stellate cells (PaSCs) caused by inflammation of the chronic pancreas plays a pivotal role in the pathology of pancreatic fibrosis and the malignant phenotype of PDAC. However, the central role of activated PaSCs in acinar-to-ductal metaplasia (ADM) remains unknown. Objective: In the present study, we investigated the link between pancreatic fibrosis and ADM and the possible underlying mechanism. Methods: A caerulein-treated mouse CP model was established, and Masson trichrome histochemical stain and transmission electron microscope (TEM) were used to observe stromal fibrosis and cell ultrastructure, respectively. The expression of amylase and cytokeratin 19 (CK19), mitochondria respiration, and reactive oxygen species (ROS) were detected in vitro in the co-culture model of primary pancreatic acinar cells and PaSCs. Results: The activation of PaSCs and pancreatic fibrosis were accompanied by ADM in pancreatic parenchyma in caerulein-treated mice, which was verified by the co-cultivation experiment in vitro. Furthermore, we showed that activated PaSCs promote ADM by disrupting mitochondrial respiration and releasing ROS. The expression of inflammation-and ADM-related genes, including S100A8, S100A9, and CK19, was observed to be up-regulated in pancreatic acinar cells in the presence of activated PaSCs. The expression of S100A9 and CK19 proteins was also up-regulated in acinar cells co-cultured with activated PaSCs. Conclusion: The manipulation of mitochondrial respiration and ROS release is a promising preventive and/or therapeutic strategy for PDAC, and S100A9 is expected to be a therapeutic target to block the ADM process induced by the activation of PaSCs.

Invasive and Non-Invasive Diagnosis of Pancreatic Fibrosis in Patients with Complicated Forms of Chronic Pancreatitis

The purpose of the study was to identify the patterns of changes in the state of the parenchyma of the pancreas in patients with complicated forms of chronic pancreatitis with evaluation of the diagnostic effectiveness of shear wave elastometry (graphy). Materials and methods. For the period from 2006 to 2018 58 patients with complicated forms of chronic pancreatitis were examined. The average age of patients is (47.1±3.2) years old. The medical history ranged from 3 to 15 years. The basis of morphological studies were biopsies of the pancreas obtained during surgery. Ultrasound elastometry and pancreatic parenchymal elastography were performed by transcutaneous shear wave approach in Shear Wave Elastography. Software consistency was assessed by the nature of the color mapping. Results and discussion. The morphometry of the volume parts of the structural components of the pancreas showed that with the development of complicated chronic pancreatitis there is an increase in the area of fibrous tissue and a decrease in the area of acinar components. The proof of this is the strong inverse relationship between the degree of fibrosis and the volume fraction of acinar tissue (r= -0.83; р <0.05), as well as the direct relationship between the degree of fibrosis and the volume fraction of connective tissue (r=0.61; р <0.05). If at a fibrosis of the III degree acinar tissue occupied (25.39±2.01)%, connective – (64.33±3.85)%, fatty – (6.42±4.48)%, at a fibrosis of the IV degree noted the following: the proportion of acinar tissue was only (2.86±0.76)%, connective – (74.11±4.17)%, and (20.14±4.29)% was adipose tissue. Such manifestations indicated severe irreversible changes in the external secretory function of the pancreas. When assessing changes in the stiffness of the pancreatic parenchyma with the deepening of fibrosis processes and data from transcutaneous shear wave elastography, it was found that the degree of fibrosis according to morphological data correlated with the degree of fibrosis according to shear wave elastography, r = 0.71; p <0.05. The following patterns were noted. Grade II pancreatic fibrosis was characterized by intralobular fibrosis, which covered 26-50% of the gland area, which corresponded to the shear wave elastography data in green-blue color (5.98-7.05 kPa). Grade III pancreatic fibrosis corresponded to intralobular fibrosis, which covered 51-75% of the gland area in shear wave elastography in green-yellow color (7.06-9.06 kPa). Grade IV pancreatic fibrosis was characterized by intralobular fibrosis, which covered 76-100% of the gland area, which corresponded to shear wave elastography data in yellow-red color (> 9.07 kPa). Conclusion. Thus, the objectification of shear wave elastography indicators of the pancreas based on the correlation of histological evaluation and morphometric indicators of structural changes in the pathological process allows to consider transcutaneous shear wave elastography as a promising and reliable method of non-invasive diagnosis of fibrosis in chronic pancreatitis

Dahuang Danshen Decoction Inhibits Pancreatic Fibrosis by Regulating Oxidative Stress and Endoplasmic Reticulum Stress

Background. In Traditional Chinese Medicine (TCM), Dahuang Danshen decoction (DD) is used to treat pancreatic fibrosis. Pancreatic fibrosis is a typical manifestation of chronic pancreatitis (CP), which affects the digestive system. The therapeutic mechanisms of DD in pancreatic fibrosis are unclear. Aim. This study aimed to investigate the regulatory mechanisms of DD on oxidative stress and endoplasmic reticulum stress in CP. Materials and Methods. Experimental rats were intraperitoneally injected with 500 mg/kg BW of diethyldithiocarbamate (DDC) twice a week for six weeks to induce CP. At the same time, DD was administered orally at daily doses of 1.37 g/kg BW, 2.74 g/kg BW, and 5.48 g/kg BW to evaluate its treatment effects on CP. After all treatments, pancreatic tissues were harvested and subjected to H&E staining. Transmission electron microscopy (TEM) was also performed to show the endoplasmic reticulum structure in the pancreatic tissues. Immunohistochemistry was used to detect the α-SMA expression level in the pancreatic tissues. Metabolomics analysis of the serum and proteomics analysis of the pancreatic tissues were performed to reveal the changes of endogenous metabolites and proteins, respectively. Concentrations of GSH, MDA, SOD, ROS, col-1, and col-3 were determined using corresponding kits. The western blotting method was used to determine the protein levels of Keap-1, HO-1, NQO1, Nrf2, GRP, JNK, and caspase 12. The pancreatic mRNA levels of NQO1, GPX1, HO-1, GST-π, GRP, JNK, and caspase 12 were also determined by quantitative PCR. The interactions between TCM components and Keap-1 were investigated by molecular docking modeling. Results. The pathohistological results demonstrated that DD could ameliorate DDC-induced CP in vivo, indicated by reduction of α-SMA, col-1, col-3, TNF-α, and IL-6. DD increased serum levels of GSH and SOD but reduced pancreatic ROS. DD decreased cytoplasmic Keap-1 and increased Nrf2 nuclear localization. Correspondingly, DD increased the expression levels of Nrf2 downstream antioxidant genes NQO1, GPX1, HO-1, and GST-π. DD also decreased ERS hallmarks caspase 12 cleavage and GRP expression. Eventually, DD inhibited PSC activation by reducing JNK phosphorylation and MMK-3/p38 expression. Molecular docking analysis showed that salvianolic acid B and emodin had a good binding affinity toward Keap-1. Conclusions. These results demonstrated that DD could ameliorate the oxidative and endoplasmic reticulum stress through releasing Nrf2 from Keap-1 binding and inducing the downstream antioxidant enzymes. As a result, DD could thwart pancreatic fibrosis by inhibiting PSCs activation, which was induced by OS and ERS through JNK and MMK3/p38 pathways.

Milk Fat Globule-EGF Factor 8 Alleviates Pancreatic Fibrosis by Inhibiting ER Stress-Induced Chaperone-Mediated Autophagy in Mice

Pancreatic fibrosis is an important pathophysiological feature of chronic pancreatitis (CP). Our recent study has shown that milk fat globule-EGF factor 8 (MFG-E8) is beneficial in acute pancreatitis. However, its role in CP remained unknown. To study this, CP was induced in male adult Mfge8-knockout (Mfge8-KO) mice and wild type (WT) mice by six intraperitoneal injections of cerulein (50 μg/kg/body weight) twice a week for 10 weeks. The results showed that knockout of mfge8 gene aggravated pancreatic fibrosis after repeated cerulein injection. In WT mice, pancreatic levels of MFG-E8 were reduced after induction of CP and administration of recombinant MFG-E8 alleviated cerulein-induced pancreatic fibrosis. The protective effect of MFG-E8 in CP was associated with reduced autophagy and oxidative stress. In human pancreatic stellate cells (PSCs), MFG-E8 inhibited TGF-β1-induced ER stress and autophagy. MFG-E8 downregulated the expression of lysosomal associated membrane protein 2A (LAMP2A), a key factor in ER stress-induced chaperone-mediated autophagy (CMA). QX77, an activator of CMA, eliminated the effects of MFG-E8 on TGF-β1-induced PSC activation. In conclusion, MFG-E8 appears to mitigate pancreatic fibrosis via inhibiting ER stress-induced chaperone-mediated autophagy. Recombinant MFG-E8 may be developed as a novel treatment for pancreatic fibrosis in CP.

Pancreatic Fibrosis (Early Chronic Pancreatitis) as Emerging Diagnosis in Structural Causes of Dyspepsia: Evidence from Endoscopic Ultrasonography and Shear Wave Elastography

A new concept for the diagnosis and management of non-functional dyspepsia in guidelines was lacking in the past decade. Medical advancement has proven pancreatic fibrosis (essential image evidence of early chronic pancreatitis) to be a cause of dyspepsia and related to pancreatic exocrine dysfunction. This study aimed to analyze the clinical picture, biomarker, and percentage of pancreatic fibrosis in the dyspeptic population. A total of 141 consecutive patients were retrospectively enrolled. They were diagnosed with peptic ulcer disease, 9.2% (n = 13); pancreatic fibrosis, 17% (n = 24); pure Helicobacter pylori infection, 19.9% (n = 28); functional dyspepsia, 53.2% (n = 75); and chronic pancreatitis, 0.7% (n = 1). Among those with pancreatic fibrosis, (n = 24), 11 were diagnosed on the basis of a pancreatic acoustic radiation force impulse exceeding 1.4 m/s, and the remaining 13 were diagnosed with early chronic pancreatitis with at least three of the Japanese endoscopic ultrasonography criteria. The anatomic distribution of parenchymal criteria of early chronic pancreatitis was head, 53%; body, 38%; and tail, 9%. There were 17 cases (71%, 17/24) without Helicobacter pylori and whose dyspepsia improved after pancreatic enzyme replacement with a ratio of 82.3% (14/17). Of the 141 cases, 19 received gastric emptying scintigraphy and Western blot analysis of chromogranin-A in duodenal mucosa. Delayed gastric emptying was more common in functional dyspepsia and chromogranin-A was expressed more in pancreatic fibrosis. In conclusion, pancreatic fibrosis (including early chronic pancreatitis) outnumbered peptic ulcer disease in the dyspeptic population and pancreatic enzyme therapy was effective for 82% of cases. In early chronic pancreatitis, pancreatic fibrosis is dominant in the head location, and duodenum mucosa chromogranin-A is a potential biomarker with increased expression in an age-matched manner.