Serum elastase-1 predicts malignancy in intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND

The indication for surgical resection of intraductal papillary mucinous neoplasms (IPMNs) is defined by imaging features, such as mural nodules. Although carbohydrate antigen (CA) 19-9 was selected as a parameter for worrisome features, no serum biomarkers were considered when deciding on surgical indications in the latest international consensus guideline. In this study, we assessed whether clinical factors, imaging findings, and serum biomarkers are useful in predicting malignant IPMNs.

METHODS

A total of 234 resected IPMN cases in Chiba University Hospital from July 2005 to December 2021 were retrospectively analyzed.

RESULTS

Among the 234 patients with resected IPMNs diagnosed by preoperative imaging, 117 were diagnosed with malignant pathologies (high-grade dysplasia and invasive IPMNs) according to the histological classification. In the multivariate analysis, cyst diameter ≥30 mm; p = 0.035), enhancing mural nodules on multidetector computed tomography (≥5 mm; p = 0.018), and high serum elastase-1 (≥230 ng/dl; p = 0.0007) were identified as independent malignant predictors, while CA19-9 was not. Furthermore, based on the receiver operator characteristic curve analyses, elastase-1 was superior to CA19-9 for predicting malignant IPMNs. Additionally, high serum elastase-1 levels (≥230 ng/dl; p = 0.0093) were identified as independent predictors of malignant IPMNs in patients without mural nodules on multidetector computed tomography (MDCT) in multivariate analysis.

CONCLUSION

The serum elastase-1 level was found to be a potentially useful biomarker for predicting malignant IPMNs.

Etiology and Morphology Impact on the Clinical Course of Chronic Pancreatitis

BACKGROUND

Symptoms caused by chronic pancreatitis (CP) are common but often elusive hampering therapeutic decisions. Though correlations of morphologic findings in imaging and clinical appearance remain vague. We aimed in investigating whether a distinct combination of clinical parameters can better define the extent of pancreatic insufficiency and disease burden.

METHODS

Data from 350 CP patients were evaluated retrospectively from a single center data base following predefined criteria: (i) confirmed CP, (ii) endoscopic ultrasound (EUS) plus (iii) fecal elastase-1 testing, (iv) age ≥18 years, and (v) Cambridge Score ≥1 on EUS evaluation.

RESULTS

In total, 182 patients (137 male, 45 female) fulfilled criteria. Median age was 52 years (range 19-88 years). Etiology distributed as follows: idiopathic 50%, alcohol 42.3%, autoimmune 7.7%. Totally, 56.6% of patients suffered from chronic pain that was significantly associated with male sex and younger age. Stool elastase-1 activity discriminated exocrine pancreatic function in Cambridge IV significantly better than in lower stages. Similarly, the endocrine function was significantly more reduced in Cambridge IV CP. Multinominal regression analysis revealed (i) presence of diabetes, (ii) presence of complications, and (iii) extent of Cambridge score as main determinants for exocrine impairment.

CONCLUSION

A high disease burden is linked to extensive morphological alterations in EUS, while pain is more frequent in younger and male patients. The etiology of CP predicts the course of disease in terms of complications.

Binding of elastase-1 and enterocytes facilitates Trichinella spiralis larval intrusion of the host's intestinal epithelium

Elastase-1 is one member of serine protease family, distributes in organisms widely and plays a crucial role in the invasion and development of Trichinella spiralis. In order to identify the binding of T. spiralis elastase-1 (TsEla) with host's intestinal epithelial cells (IECs) and its role in Trichinella larval intrusion, TsEla gene was cloned and expressed in our previous study. The recombinant TsEla (rTsEla) has the enzymatic activity to degrade specific peptide substrate. A specific binding between rTsEla and IECs was detected by Far Western blot and ELISA. In an in vitro invasion assay, rTsEla promoted the larval intrusion, whereas anti-rTsEla serum inhibited the larval penetration. The larval intrusion was also suppressed after the silencing of TsEla by siRNA. Silencing of TsEla gene by siRNA-291 meditated RNA interference suppressed TsEla protein expression, reduced the worm infectivity, development and reproductive capacity. These results indicated that TsEla plays an important role in the T. spiralis intrusion of host's intestinal epithelia, and it could be a prospective vaccine molecular target against T. spiralis infection.

Molecular characterization of a Trichinella spiralis elastase-1 and its potential as a diagnostic antigen for trichinellosis

BACKGROUND

Trichinella spiralis muscle larval (ML) excretion/secretion (ES) antigen is the most widely used diagnostic antigen of trichinellosis, but preparation of ES antigen requires collecting worms from infected animals, and detection of specific IgG against ML ES antigen may result in a false negative at the early stage of infection. The aim of the study was to characterize T. spiralis elastase-1 (TsEla) and to evaluate its potential as diagnostic antigen for trichinellosis.

METHODS

The complete cDNA sequences of the TsEla gene were cloned and expressed, and recombinant (rTsEla) was purified. TsEla transcription and expression in different T. spiralis life-cycle stages was investigated by qPCR and western blotting, and its location in the nematodes was evaluated using an immunofluorescence assay (IFA). The antigenicity of rTsEla was investigated by western blotting analysis and ELISA. Anti-Trichinella IgG, IgM and IgE of experimentally infected mice and specific IgG antibodies of trichinellosis patients were assayed by rTsEla-ELISA and ES-ELISA.

RESULTS

The results of the qPCR and western blotting showed that TsEla was expressed in various T. spiralis life stages. Natural TsEla was detected in the soluble proteins and ES proteins of different life stages. IFA revealed that TsEla was identified in the whole nematodes of various stages, especially in the cuticle, stichosome and genital primordium of the parasite. Serum anti-Trichinella IgM, IgG and IgE in infected mice was first detected by rTsEla-ELISA at 6, 10 and 12 days post-infection (dpi), and reached 100% at 8, 14 and 14 dpi, respectively. When rTsEla-ELISA and ES-ELISA were used to detect anti-Trichinella IgG in sera of trichinellosis patients, the sensitivity was 97.37% (37/38) and 89.74% (34/38) (P > 0.05), and the specificity was 99.10% (220/222) and 98.20% (218/222), respectively (P > 0.05). The rTsEla cross-reacted with only one serum sample out of 20 samples from paragonimiasis patients and 7 samples from clonorchiasis patients.

CONCLUSIONS

rTsEla is valuable to early diagnosis of trichinellosis and could be an alternative diagnostic antigen to the ML ES antigens.