Protein expression profiling reveals distinctive changes in serum proteins associated with chronic pancreatitis

Decreased circulating retinol binding protein is an independent risk factor for local complications of acute pancreatitis

BACKGROUND

Acute pancreatitis is a common acute abdomen in China. There is a decrease of serum retinol-binding protein (RBP) in some patients, but its clinical significance is not clear.

AIM

To explore the relationship between serum RBP and the severity and complications of AP.

METHODS

The clinical data of AP patients admitted to Jinling Hospital in 2018 within 7 days of onset were analyzed retrospectively. The enrolled patients were divided into either a normal RBP (NRBP) group or a low RBP (LRBP) group according to the serum RBP level. The baseline characteristics, severity, and prognosis of disease were compared between the two groups. Logistic regression analysis was used to explore the independent risk factors for local complications. Receiver operating characteristic (ROC) curve was drawn to evaluate the performance of serum RBP in predicting complications.

RESULTS

A total of 176 patients were enrolled, including 41 in the NRBP group and 135 in the LRBP group. The severity of AP in the LRBP group was significantly more severe than that of the NRBP group (MAP: 15.6% vs 39.0%, MSAP: 53.3% vs 29.3%, SAP: 31.1% vs 31.7%; P < 0.05). The incidence of acute necrotic collection was 70.4% in the LRBP group, significantly higher than that (52.1%) of the NRBP group (P < 0.05). The serum level of RBP in patients with local complications was significantly lower than that in patients without (24.00 (15.00, 27.50) mg/L vs 12.00 (9.00, 22.00) mg/L, P < 0.05). The AUC of serum RBP for predicting local complications was 0.708 (95%CI: 0.615-0.801) and the cut-off value was 15.5 mg/L with a sensitivity 60.4% and specificity 75.7%. The decrease of serum RBP was an independent risk factor for local complications (OR = 5.306, P = 0.003, 95%CI: 1.771-15.896).

CONCLUSION

The level of serum RBP in the acute phase could predict the occurrence of local complications of AP, but has no significant correlation with systemic inflammatory response and remote organ failure.

Exocrine pancreatic insufficiency in type 1 and type 2 diabetes mellitus: do we need to treat it? A systematic review

The exocrine and endocrine pancreata are very closely linked both anatomically and physiologically. Abdominal symptoms such as nausea, bloating, diarrhea, steatorrhea, and weight loss can often occur in diabetic patients. Impairments of the exocrine pancreatic function seem to be a frequent complication of diabetes mellitus; however, they are largely overlooked. The aim of this paper is to provide an overview of the current concepts of exocrine pancreatic insufficiency (PEI) in diabetes mellitus. The prevalence and symptoms of PEI in diabetes mellitus, the pathomechanism, and difficulties of diagnosis and therapy of PEI are summarized in this systematic review.

A Cost-Effective High-Throughput Plasma and Serum Proteomics Workflow Enables Mapping of the Molecular Impact of Total Pancreatectomy with Islet Autotransplantation

Blood is an ideal body fluid for the discovery or monitoring of diagnostic and prognostic protein biomarkers. However, discovering robust biomarkers requires the analysis of large numbers of samples to appropriately represent interindividual variability. To address this analytical challenge, we established a high-throughput and cost-effective proteomics workflow for accurate and comprehensive proteomics at an analytical depth applicable for clinical studies. For validation, we processed 1 μL each from 62 plasma samples in 96-well plates and analyzed the product by quantitative data-independent acquisition liquid chromatography/mass spectrometry; the data were queried using feature quantification with Spectronaut. To show the applicability of our workflow to serum, we analyzed a unique set of samples from 48 chronic pancreatitis patients, pre and post total pancreatectomy with islet autotransplantation (TPIAT) surgery. We identified 16 serum proteins with statistically significant abundance alterations, which represent a molecular signature distinct from that of chronic pancreatitis. In summary, we established a cost-efficient high-throughput workflow for comprehensive proteomics using PVDF-membrane-based digestion that is robust, automatable, and applicable to small plasma and serum volumes, e.g., finger stick. Application of this plasma/serum proteomics workflow resulted in the first mapping of the molecular implications of TPIAT on the serum proteome.

[Nutritional status in patients with chronic pancreatitis]

Chronic pancreatitis (CP) is an inflammatory disease of the pancreas, accompanied by damage to the functioning parenchyma and ducts to develop irreversible structural changes (fibrosis, calcification) and irreparable loss of the endocrine and exocrine functions of this organ. Maldigestion is a typical outcome of CP of any etiology with a long-term history. Fat malabsorption is considered as a basis for malnutrition in patients with CP. The severity of malnutrition in patients with CP correlates with three major pathogenetic factors: primary nutrient deficiency, pancreatic maldigestion and secondary malabsorption syndrome (nutrient loss), hypermetabolism that is caused by an inflammatory process in the pancreas and that determines the severity of the disease. Malnutrition in patients with CP is not just a complication of this disease, but has an important impact on its course. Patients with severe malnutrition are noted to have the significantly lower activity of pancreatic enzymes in the duodenal contents, feces, and blood, which is correlated with the smaller blood amount of total protein and albumin.

Serum protein signatures differentiating autoimmune pancreatitis versus pancreatic cancer

Autoimmune pancreatitis (AIP) is defined by characteristic lymphoplasmacytic infiltrate, ductal strictures and a pancreatic enlargement or mass that can mimic pancreatic cancer (PaCa). The distinction between this benign disease and pancreatic cancer can be challenging. However, an accurate diagnosis may pre-empt the misdiagnosis of cancer, allowing the appropriate medical treatment of AIP and, consequently, decreasing the number of unnecessary pancreatic resections.

Mass spectrometry (MS) and two-dimensional differential gel electrophoresis (2D-DIGE) have been applied to analyse serum protein alterations associated with AIP and PaCa, and to identify protein signatures indicative of the diseases. Patients' sera were immunodepleted from the 20 most prominent serum proteins prior to further 2D-DIGE and image analysis. The identity of the most-discriminatory proteins detected, was performed by MS and ELISAs were applied to confirm their expression. Serum profiling data analysis with 2D-DIGE revealed 39 protein peaks able to discriminate between AIP and PaCa. Proteins were purified and further analysed by MALDI-TOF-MS. Peptide mass fingerprinting led to identification of eleven proteins. Among them apolipoprotein A-I, apolipoprotein A-II, transthyretin, and tetranectin were identified and found as 3.0-, 3.5-, 2-, and 1.6-fold decreased in PaCa sera, respectively, whereas haptoglobin and apolipoprotein E were found to be 3.8- and 1.6-fold elevated in PaCa sera. With the exception of haptoglobin the ELISA results of the identified proteins confirmed the 2D-DIGE image analysis characteristics. Integration of the identified serum proteins as AIP markers may have considerable potential to provide additional information for the diagnosis of AIP to choose the appropriate treatment.

Diagnosis and treatment of pancreatic exocrine insufficiency

Pancreatic exocrine insufficiency is an important cause of maldigestion and a major complication in chronic pancreatitis. Normal digestion requires adequate stimulation of pancreatic secretion, sufficient production of digestive enzymes by pancreatic acinar cells, a pancreatic duct system without significant outflow obstruction and adequate mixing of the pancreatic juice with ingested food. Failure in any of these steps may result in pancreatic exocrine insufficiency, which leads to steatorrhea, weight loss and malnutrition-related complications, such as osteoporosis. Methods evaluating digestion, such as fecal fat quantification and the ¹³C-mixed triglycerides test, are the most accurate tests for pancreatic exocrine insufficiency, but the probability of the diagnosis can also be estimated based on symptoms, signs of malnutrition in blood tests, fecal elastase 1 levels and signs of morphologically severe chronic pancreatitis on imaging. Treatment for pancreatic exocrine insufficiency includes support to stop smoking and alcohol consumption, dietary consultation, enzyme replacement therapy and a structured follow-up of nutritional status and the effect of treatment. Pancreatic enzyme replacement therapy is administered in the form of enteric-coated minimicrospheres during meals. The dose should be in proportion to the fat content of the meal, usually 40-50000 lipase units per main meal, and half the dose is required for a snack. In cases that do not respond to initial treatment, the doses can be doubled, and proton inhibitors can be added to the treatment. This review focuses on current concepts of the diagnosis and treatment of pancreatic exocrine insufficiency.

Altered plasma apolipoprotein modifications in patients with pancreatic cancer: protein characterization and multi-institutional validation

Background

Among the more common human malignancies, invasive ductal carcinoma of the pancreas has the worst prognosis. The poor outcome seems to be attributable to difficulty in early detection.

Methods

We compared the plasma protein profiles of 112 pancreatic cancer patients with those of 103 sex- and age-matched healthy controls (Cohort 1) using a newly developed matrix-assisted laser desorption/ionization (oMALDI) QqTOF (quadrupole time-of-flight) mass spectrometry (MS) system.

Results

We found that hemi-truncated apolipoprotein AII dimer (ApoAII-2; 17252 m/z), unglycosylated apolipoprotein CIII (ApoCIII-0; 8766 m/z), and their summed value were significantly decreased in the pancreatic cancer patients [P = 1.36×10⁻²¹, P = 4.35×10⁻¹⁴, and P = 1.83×10⁻²⁴ (Mann-Whitney U-test); area-under-curve values of 0.877, 0.798, and 0.903, respectively]. The significance was further validated in a total of 1099 plasma/serum samples, consisting of 2 retrospective cohorts [Cohort 2 (n = 103) and Cohort 3 (n = 163)] and a prospective cohort [Cohort 4 (n = 833)] collected from 8 medical institutions in Japan and Germany.

Conclusions

We have constructed a robust quantitative MS profiling system and used it to validate alterations of modified apolipoproteins in multiple cohorts of patients with pancreatic cancer.

Serum nutritional markers for prediction of pancreatic exocrine insufficiency in chronic pancreatitis

BACKGROUND

Methods for evaluation of pancreatic exocrine insufficiency (PEI) are expensive, labor intensive, and not available at many institutions. The aim of this study was to investigate if PEI in chronic pancreatitis (CP) can by predicted by nutritional markers in blood.

METHODS

A retrospective analysis of a prospectively collected database of CP patients was performed. Diagnosis of CP was based on endoscopic ultrasonography or magnetic resonance imaging. PEI was investigated by the (13)C-mixed triglyceride breath test. Hemoglobin, mean corpuscular volume, lymphocytes, prothrombin time, and serum levels of total protein, albumin, prealbumin, retinol binding protein, cholesterol, triglycerides, amylase, folic acid, vitamin B12, HbA1C, transferrin, ferritin, magnesium and zinc were analyzed.

RESULTS

114 patients were included in the study (97 males, mean age 48.1 years, 54 with alcohol etiology), 38 (33%) suffered from PEI. Magnesium below 2.05 mg/dL, hemoglobin, albumin, prealbumin and retinol binding protein below lower limit of normal and HbA1C above upper limit of normal were associated with PEI in univariate analysis. Magnesium below 2.05 mg/dL detected PEI with a sensitivity, specificity and positive and negative predictive values of 0.88 (95% confidence interval, 0.66-0.97), 0.66 (0.48-0.80), 0.58 (0.39-0.75) and 0.91 (0.73-0.98), respectively. The corresponding values were 1.00 (0.80-1.00), 0.55 (0.38-0.71), 0.52 (0.34-0.69) and 1.00 (0.82-1.00)) if one or more pathological tests among parameters significantly associated with PEI in was used as a positive test for PEI.

CONCLUSION

Serum nutritional markers can be used to predict the probability of PEI in CP and provide guidance in decisions on enzyme replacement therapy.

Identification of serum proteins involved in pancreatic cancer cachexia

AIMS

Treatment of cachexia requires pharmacological intervention which, in turn, requires knowledge of the mediators and processes. Cachexia markers that are specifically expressed in pancreatic cancer and secreted into the blood circulation have yet to be identified. The aim of our study was to investigate the serum protein profiles and protein alterations associated with cachexia and to identify potential disease protein biomarkers indicative for this syndrome.

MAIN METHODS

Serum samples from cachectic and non-cachectic patients undergoing pancreatic cancer (PaCa) surgery and controls were investigated by Surface Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS). The identity of detected discriminatory markers was determined by a combination of protein fractionation, chromatographic purification steps, gel electrophoresis, and mass spectrometry.

KEY FINDINGS

Using Cu-IMAC array and CM-10 array based SELDI-TOF-MS. we identified eleven up- and four down-regulated proteins associated with cachexia. CiphergenExpress analysis revealed four disease-associated protein features (38559Da, 9138Da, 8925Da and 3358Da) that were elevated by a factor of 2.3, 1.7, 1.4 and 1.4, respectively. Zinc-α2-glycoprotein (ZAG), apolipoproteins apo C-II and apo C-III and glucagon-like peptide-1 (GLP-1) were identified as markers for PaCa-associated cachexia syndrome. ZAG levels were additionally evaluated in serum and tissue samples by ELISA and immunohistochemistry and the obtained data confirmed the SELDI-TOF-MS results.

SIGNIFICANCE

The identified proteins could be routinely and reliably measured in the serum of patients and provide an elegant non-invasive approach for early diagnosis of cachectic pancreatic cancer patients. Controlling ZAG and GLP-1 activity could be beneficial in the management of cancers and cachexia-induced conditions.

New pre-analytical approach for the deep proteome analysis of sera from pancreatitis and pancreas cancer patients

The presence of high-abundance proteins and the wide dynamic range of protein-distribution complicates the proteome analysis of crude serum. The aim was to establish a new preanalytical protocol for analysis of the deep serum-proteome for biomarker discovery.

METHODS

We investigated the stability and functionality of ProteoMiner™ and tested the new protocol by SELDI-TOF-MS profiling with serum samples obtained from patients with different pancreatic diseases.

RESULTS

We developed a high-throughput protocol and proved the convenience of ProteoMiner™ in the 96-well format to provide insights into the deep serum proteome and facilitate the detection of novel serum biomarkers. Serum samples spiked with defined amounts of insulin, processed with ProteoMiner™ and analyzed by SELDI-TOF-MS revealed that the concentration of the spiked insulin was not altered by ProteoMiner™ treatment.

CONCLUSION

ProteoMiner™ technology is robust preanalytical step and can be used in a high-throughput format for analysis of low-abundant proteins in serum.

Systems biology coupled with label-free high-throughput detection as a novel approach for diagnosis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a treatable and preventable disease state, characterised by progressive airflow limitation that is not fully reversible. Although COPD is primarily a disease of the lungs there is now an appreciation that many of the manifestations of disease are outside the lung, leading to the notion that COPD is a systemic disease. Currently, diagnosis of COPD relies on largely descriptive measures to enable classification, such as symptoms and lung function. Here the limitations of existing diagnostic strategies of COPD are discussed and systems biology approaches to diagnosis that build upon current molecular knowledge of the disease are described. These approaches rely on new 'label-free' sensing technologies, such as high-throughput surface plasmon resonance (SPR), that we also describe.

Chronic pancreatitis

PURPOSE OF REVIEW

As in previous reviews in this journal, this review is focused on the most important new observations in chronic pancreatitis made in the last year.

RECENT FINDINGS

Important observations included the search for biomarkers and alternative methods for the detection of early chronic pancreatitis; stellate cell activation and their role in fibrogenesis; the natural history of chronic pancreatitis; reports outlining the complexity in diagnosis of autoimmune pancreatitis; emerging roles of endoscopic ultrasound and magnetic resonance cholangiopancreatography in chronic pancreatitis diagnosis; a better understanding of neurobiology of chronic pancreatitis pain; and the potential role of surgery as first-line therapy in advanced chronic pancreatitis.

SUMMARY

In 2007, major advances were made in our understanding of central processing in chronic pancreatitis pain. New techniques are being utilized in search of a better means to diagnose early chronic pancreatitis. Important prospective studies are emerging, which compare endoscopic and surgical interventions. Furthermore, the complexities of diagnosing autoimmune pancreatitis are being recognized. Overall, the future is promising as advances in genomic and proteomic techniques are applied to improve our understanding of chronic pancreatitis.