Resistin: New serum marker for predicting severity of acute pancreatitis

Managing complicated pancreatitis with more knowledge and a bigger toolbox!

Acute pancreatitis (AP) is a heterogeneous inflammation of the pancreas, most frequently attributable to gallstones or alcohol. AP accounts for an estimated 300 000 patients admitted each year in the USA, and an estimated US$2.6 billion/year in hospitalization costs. Disease severity is classified as mild, moderate, or severe, dependent on the presence or degree of concomitant organ failure. Locally, pancreatitis may be complicated by fluid collections, necrosis, infection, and hemorrhage. Infection of necrotizing pancreatitis (NP) is associated with a doubling of mortality risk. The modern management of AP is evolving. Recent data suggest a shift from normal saline to lactated Ringer's solution, and from aggressive to more judicious volume resuscitation. Similarly, while historical wisdom advocated keeping patients nothing by mouth to 'rest the pancreas', recent data convincingly show fewer complications and reduced mortality with early enteral nutrition, when tolerated by the patient. The use of antibiotics in NP is controversial. Current recommendations suggest reserving antibiotics for cases with highly suspected or confirmed infected necrosis, as well as in patients with biliary pancreatitis complicated by acute cholecystitis or cholangitis. Regarding the management of local complications, control of acute hemorrhage can be attained either endovascularly or via laparotomy. Abdominal compartment syndrome is associated with a mortality risk of 50%-75%. Routine monitoring of intra-abdominal pressure is recommended in patients at high risk. Pancreatic pseudocysts require intervention in symptomatic patients or those with infection or other complications. Endoscopic transmural drainage may be considered as the first step when technically feasible. Necrotizing pancreatitis without suspicion of infection is often managed medically, while the delay, drain, debride approach remains the standard of care for the vast majority of infected pancreatic necrosis. Robotic surgery, in appropriately selected patients, allows for a one-step approach, and merits further study to explore its initially promising results.

Diagnostic value of CRP for predicting the severity of acute pancreatitis: a systematic review and meta-analysis

BACKGROUND

C-reactive protein (CRP) is a pentameric protein commonly used as a biomarker of inflammation or stress response which can be obtained during routine blood tests. Therefore, we conducted a systematic review and meta-analysis to explore its ability to predict the severity of acute pancreatitis (AP). This meta-analysis was registered in the PROSPERO system (registration number: CRD42022353769).

METHODS

41 studies with 6156 cases of acute pancreatitis, retrieved from PubMed, Cochrane Library, Springer, and Embase databases, were incorporated. We calculated the pooled estimates for predicting the severity of acute pancreatitis based on CRP levels. We also calculated the combined negative likelihood ratio (NLR), combined positive likelihood ratio (PLR) and combined diagnostic odds ratio (DOR) using a bivariate mixed model. Sensitivity analysis was used to examine the robustness of the results. Factors associated with heterogeneity were identified by meta-regression analysis. A summary operating characteristic (SROC) curve was generated to assess the diagnostic value of CRP in predicting severe acute pancreatitis. Fagan's test was used to calculate likelihood ratios and post-test probabilities, and publication bias was gauged by asymmetry tests.

RESULTS

SROC analysis yielded an AUC of 0.85 (95%CI: 0.81-0.88) with a sensitivity of 0.76 (95%CI: 0.69-0.83) and specificity of 0.79 (95%CI: 0.74-0.83). The combined NLR, PLR and DOR were 0.30 (0.23-0.40), 3.66 (2.94-4.55) and 12.19 (8.05-18.44) respectively. Sensitivity analysis demonstrated the stability of our results after omitting any study. Finally, meta-regression analysis indicated that the description of the reference test, prospective design, blinding method and spectrum of the disease could account for heterogeneity in this meta-analysis.

CONCLUSION

CRP has significant value as a biomarker for assessing AP severity. Besides, other parameters such as patient history, physical signs, and imaging should be considered to determine disease severity.

Immune markers of severe acute pancreatitis

PURPOSE OF REVIEW

Acute pancreatitis is a common acute inflammatory disorder of the pancreas, and its incidence has been increasing worldwide. Approximately 10% of acute pancreatitis progresses to severe acute pancreatitis (SAP), which carries significant morbidity and mortality. Disordered immune response to pancreatic injury is regarded as a key event that mediates systemic injury in SAP. In this article, we review recent developments in immune biomarkers of SAP and future directions for research.

RECENT FINDINGS

Given the importance of the NLRP3-inflammasome pathway in mediating systemic inflammatory response syndrome and systemic injury, recent studies have investigated associations of SAP with systemic levels of activators of NLRP3, such as the damage associated molecular patterns (DAMPs) for the first time in human SAP. For example, circulating levels of histones, mitochondrial DNAs, and cell free DNAs have been associated with SAP. A panel of mechanistically relevant immune markers (e.g., panel of Angiopoeitin-2, hepatocyte growth factor, interleukin-8 (IL-8), resistin and sTNF-α R1) carried higher predictive accuracies than existing clinical scores and individual immune markers. Of the cytokines with established relevance to SAP pathogenesis, phase 2 trials of immunotherapies, including tumor necrosis factor (TNF)-alpha inhibition and stimulation of IL-10 production, are underway to determine if altering the immunologic response can reduce the severity of acute pancreatitis (AP).

SUMMARY

Circulating systemic levels of various DAMPs and a panel of immune markers that possibly reflect activities of different pathways that drive SAP appear promising as predictive biomarkers for SAP. But larger multicenter studies are needed for external validation. Studies investigating immune cellular pathways driving SAP using immunophenotyping techniques are scarce. Interdisciplinary efforts are also needed to bring some of the promising biomarkers to the bedside for validation and testing for clinical utility. Studies investigating the role of and characterization of altered gut-lymph and gut-microbiota in severe AP are needed.

Predictive value of adipokines for the severity of acute pancreatitis: a meta-analysis

BACKGROUND

Severe acute pancreatitis (SAP) is a dangerous condition with a high mortality rate. Many studies have found an association between adipokines and the development of SAP, but the results are controversial. Therefore, we performed a meta-analysis of the association of inflammatory adipokines with SAP.

METHODS

We screened PubMed, EMBASE, Web of Science and Cochrane Library for articles on adipokines and SAP published before July 20, 2023. The quality of the literature was assessed using QUADAS criteria. Standardized mean differences (SMD) with 95% confidence intervals (CI) were calculated to assess the combined effect. Subgroup analysis, sensitivity analysis and publication bias tests were also performed on the information obtained.

RESULT

Fifteen eligible studies included 1332 patients with acute pancreatitis (AP). Pooled analysis showed that patients with SAP had significantly higher serum levels of resistin (SMD = 0.78, 95% CI:0.37 to 1.19, z = 3.75, P = 0.000). The difference in leptin and adiponectin levels between SAP and mild acute pancreatitis (MAP) patients were not significant (SMD = 0.30, 95% CI: -0.08 to 0.68, z = 1.53, P = 0.127 and SMD = 0.11, 95% CI: -0.17 to 0.40, z = 0.80, P = 0.425, respectively). In patients with SAP, visfatin levels were not significantly different from that in patients with MAP (SMD = 1.20, 95% CI: -0.48 to 2.88, z = 1.40, P = 0.162).

CONCLUSION

Elevated levels of resistin are associated with the development of SAP. Resistin may serve as biomarker for SAP and has promise as therapeutic target.

Eugenol Reduced ΜPO, CD45 and HMGB1 Expression and Attenuated the Expression of Leukocyte Infiltration Markers in the Intestinal Tissue in Biliopancreatic Duct Ligation-Induced Pancreatitis in Rats

Background and Objectives: Inflammation and dysregulation in the intestinal barrier function in acute pancreatitis (AP) trigger pancreatic lesions, systemic inflammatory response, and multiple organ dysfunction. Eugenol, as the main component of clove (Syzygium aromaticum), is known for its antioxidant and anti-inflammatory properties. We studied the potentially beneficial effect of eugenol in a rodent model of biliopancreatic duct ligation-induced AP. Materials and Methods: Rats were randomly divided into three groups: Sham, AP, and AP + eugenol (15 mg/kg/day). Serum TNFα, IL-6, IL-18, and resistin levels, as well as IL-6, TNFα, MPO, HMGB1, and CD45 tissue expression, were determined at various timepoints after the induction of AP. Results: Eugenol attenuated hyperemia and inflammatory cell infiltration in the intestinal mucosal, submucosal, and muscular layers. IL-6 and resistin serum levels were significantly reduced in the AP + eugenol group, while serum TNFα and IL-18 levels remained unaffected overall. TNFα pancreatic and intestinal expression was attenuated by eugenol at 72 h, while IL-6 expression was affected only in the pancreas. MPO, CD45, and HMGB1 intestinal expression was significantly reduced in eugenol-treated rats. Conclusions: Eugenol managed to attenuate the inflammatory response in the intestine in duct ligation-induced AP in rats.

Evidence-Based Approach to the Surgical Management of Acute Pancreatitis

Background  Acute pancreatitis is a significant challenge to health services. Remarkable progress has been made in the last decade in optimizing its management.

Methods  This review is a comprehensive assessment of 7 guidelines employed in current clinical practice with an appraisal of the underlying evidence, including 15 meta-analyses/systematic reviews, 16 randomized controlled trials, and 31 cohort studies.

Results  Key tenets of early management of acute pancreatitis include severity stratification based on the degree of organ failure and early goal-directed fluid resuscitation. Rigorous determination of etiology reduces the risk of recurrence. Early enteral nutrition and consideration of epidural analgesia have been pioneered in recent years with promising results. Indications for invasive intervention are becoming increasingly refined. The definitive indications for endoscopic retrograde cholangiopancreatography in acute pancreatitis are associated with cholangitis and common bile duct obstruction. The role of open surgical necrosectomy has diminished with the development of a minimally invasive step-up necrosectomy protocol. Increasing use of endoscopic ultrasound–guided intervention in the management of pancreatic necrosis has helped reduce pancreatic fistula rates and hospital stay.

Conclusion  The optimal approach to surgical management of complicated pancreatitis depends on patient physiology and disease anatomy, in addition to the available resources and expertise. This is best achieved with a multidisciplinary approach. This review provides a distillation of the recommendations of clinical guidelines and critical discussion of the evidence that informs them and presents an algorithmic approach to key areas of patient management.

α‑lipoic acid inhibits cerulein/resistin‑induced expression of interleukin‑6 by activating peroxisome proliferator‑activated receptor‑γ in pancreatic acinar cells

Cerulein‑induced pancreatitis resembles human acute pancreatitis in terms of pathological events, such as enzymatic activation and inflammatory cell infiltration in the pancreas. Cerulein is a cholecystokinin analog that increases levels of reactive oxygen species (ROS) and interleukin‑6 (IL‑6) expression level in pancreatic acinar cells. Serum levels of resistin, which is secreted from adipocytes, are reportedly higher in patients with acute pancreatitis than in healthy individuals. Previously, it was shown that the adipokine resistin can aggravate the cerulein‑induced increase in ROS levels and IL‑6 expression level in pancreatic acinar cells. Peroxisome proliferator‑activated receptor‑gamma (PPAR‑γ) is a key regulator of the transcription and expression of antioxidant enzymes, including heme oxygenase 1 (HO‑1) and catalase. α‑lipoic acid, a naturally occurring dithiol antioxidant, can prevent cerulein‑induced pancreatic damage in rats. In the present study, it was aimed to investigate whether α‑lipoic acid can attenuate the cerulein/resistin‑induced increase in IL‑6 expression and ROS levels via PPAR‑γ activation in pancreatic acinar AR42J cells. The anti‑inflammatory mechanism of α‑lipoic acid was determined using reverse transcription‑quantitative PCR, western blot analysis, enzyme‑linked immunosorbent assay, immunofluorescence staining and fluorometry. Treatment with cerulein and resistin increased ROS levels and IL‑6 expression level, which were inhibited by α‑lipoic acid in pancreatic acinar cells. α‑lipoic acid increased the nuclear translocation and expression level of PPAR‑γ and the expression levels of its target genes: HO‑1 and catalase. The PPAR‑γ antagonist GW9662 and HO‑1 inhibitor zinc protoporphyrin reversed the inhibitory effect of α‑lipoic acid on cerulein/resistin‑induced increase in ROS and IL‑6 levels. In conclusion, α‑lipoic acid inhibits the cerulein/resistin‑induced increase in ROS production and IL‑6 expression levels by activating PPAR‑γ and inducing the expression of HO‑1 and catalase in pancreatic acinar cells.

Alteration of Peripheral Resistin and the Severity of Acute Pancreatitis: A Meta-Analysis

INTRODUCTION

Resistin is a small secretory adipokine which is implicated to obesity and associated diseases. Recently, plenty of research papers have been conducted to explore the association between peripheral resistin and the severity of acute pancreatitis (AP). However, the results were controversial. In this study, we aimed to confirm the effect of peripheral resistin and the development of acute pancreatitis.

METHODS

A comprehensive online search was performed using the PubMed, Embase, Web of Science, CNKI, and Wanfang databases up through January 20, 2022. The retrieved records and their references were screened to identify additional studies. Data were extracted to calculate the pooled Hedges' g and its 95% CI, which were selected to assess peripheral resistin levels and the severity of acute pancreatitis. Subgroup analyses, sensitivity analyses, meta-regression, and publication bias tests were also undertaken based on obtained information.

RESULTS

A total of eleven studies with 892 acute pancreatitis patients were enrolled in the study. Peripheral resistin levels were significantly increased in severe acute pancreatitis compared with mild acute pancreatitis (Hedges' g = 2.092, 95% CI: 0.994-3.190, P < 0.001). Subgroup analyses based on sample types and ethnicity also showed similar results. A single study did not affect our results, which was verified by sensitivity analysis. Meta-regression analyses revealed that age, gender of the included subjects, sample size, and publication year did not moderate effects on the present results.

CONCLUSION

In our study, peripheral resistin levels were significantly elevated in patients with severe AP compared with patients with mild AP. Abnormal resistin levels may provide us some new insights in predicting the severity of AP.

Resistin and Cardiovascular Disease: A Review of the Current Literature Regarding Clinical and Pathological Relationships

Serum resistin, mainly secreted by the bone marrow, monocytes, and macrophages, contributes to many processes, including endothelial dysfunction, Vascular Smooth Muscle Cell (VSMC) proliferation, and atherothrombosis demonstrating effects on the development of hypertension and Coronary Artery Disease (CAD). Previously published clinical studies have shown that plasma resistin levels are significantly associated with cardiovascular disease risk factors and adverse clinical outcomes associated with the condition. Resistin is associated with vascular smooth muscle cell dysfunction in vitro, most plausibly due to its relationship with oxidative stress in advanced atherosclerosis whereas in vivo studies have shown resistin to be associated with intimal hyperplasia. We aimed to summarize the role of resistin on cardiovascular disease (CVD), as we could not find any review focused on the role of resistin on CVD.

Astaxanthin Inhibits Interleukin-6 Expression in Cerulein/Resistin-Stimulated Pancreatic Acinar Cells

Acute pancreatitis is a common clinical condition with increasing the proinflammatory mediators, including interleukin-6 (IL-6). Obesity is a negative prognostic factor in acute pancreatitis. Obese patients with acute pancreatitis have a higher systemic inflammatory response rate. Levels of serum resistin, an adipocytokine secreted by fat tissues, increase with obesity. Cerulein, a cholecystokinin analog, induces calcium (Ca²⁺) overload, oxidative stress, and IL-6 expression in pancreatic acinar cells, which are hallmarks of acute pancreatitis. A recent study showed that resistin aggravates the expression of inflammatory cytokines in cerulein-stimulated pancreatic acinar cells. We aimed to investigate whether resistin amplifies cerulein-induced IL-6 expression and whether astaxanthin (ASX), an antioxidant carotenoid with anti-inflammatory properties, inhibits ceruelin/resistin-induced IL-6 expression in pancreatic acinar AR42J cells. We found that resistin enhanced intracellular Ca²⁺ levels, NADPH oxidase activity, intracellular reactive oxygen species (ROS) production, NF-κB activity, and IL-6 expression in cerulein-stimulated AR42J cells, which were inhibited by ASX in a dose-dependent manner. The calcium chelator BAPTA-AM inhibited cerulein/resistin-induced NADPH oxidase activation and ROS production. Antioxidant N-acetyl cysteine (NAC) and ML171, a specific NADPH oxidase 1 inhibitor, suppressed cerulein/resistin-induced ROS production, NF-κB activation, and IL-6 expression. In conclusion, ASX inhibits IL-6 expression, by reducing Ca²⁺ overload, NADPH oxidase-mediated ROS production, and NF-κB activity in cerulein/resistin-stimulated pancreatic acinar cells. Consumption of ASX-rich foods could be beneficial for preventing or delaying the incidence of obesity-associated acute pancreatitis.

Can serum resistin predict severity of acute pancreatitis?

OBJECTIVE

Acute pancreatitis (AP) is a common disorder with high mortality in severe cases. Several markers have been studied to predict development of severe AP (SAP) including serum resistin with conflicting results. This study aimed at assessing the role of baseline serum resistin levels in predicting SAP.

METHODS

This prospective study collected data from 130 AP patients from July 2017 to Nov 2018. Parameters measured included demographic profile, serum resistin at admission, severity scores, hospital stay, surgery, and mortality. Patients were divided into two groups, severe and non-severe AP. The two groups were compared for baseline characteristics, serum resistin levels, hospital stay, surgery and mortality.

RESULTS

Among 130 patients, 53 patients had SAP. SAP patients had higher BMI, baseline CRP, APACHE II and CTSI scores (p-value 0.045, <0.001, <0.001 and 0.001, respectively). Both groups had comparable serum resistin levels. Serum resistin levels were also not different for obese and non-obese patients (p-value = 0.62). On multivariate analysis, BMI and high APACHE II score and CRP levels were found to independently predict SAP.

CONCLUSION

We found that serum resistin is not a useful marker for predicting the severity of AP and does not correlate with increasing body weight.

Management of Severe Acute Pancreatitis

Purpose of review

There have been significant advancements in different aspects of management of severe acute pancreatitis (SAP). Our review of the most recent literature focuses on severity prediction, fluid resuscitation, analgesic administration, nutrition, and endoscopic intervention for SAP and its extra-pancreatic complications.

Recent findings

Recent studies on serum cytokines for the prediction of SAP have shown superior prognostic performance when compared with conventional laboratory tests and clinical scoring systems. In patients with established SAP and vascular leak syndrome, intravenous fluids should be administered with caution to prevent intra-abdominal hypertension and volume overload. Endoscopic retrograde cholangiopancreatography improves outcomes only in AP patients with suspected cholangitis. Early enteral tube-feeding does not appear to be superior to on-demand oral feeding. Abdominal compartment syndrome is a highly lethal complication of SAP that requires percutaneous drainage or decompressive laparotomy. Endoscopic transmural drainage followed by necrosectomy (i.e., “step-up approach”) is the treatment strategy of choice in patients with symptomatic or infected walled-off pancreatic necrosis.

Summary

SAP is a complex clinical syndrome associated with a high mortality rate. Early prediction of SAP remains challenging due to the limited accuracy of the available prediction tools. Early fluid resuscitation, organ support, enteral nutrition, and prevention of/or prompt recognition of abdominal compartment syndrome remain cornerstones of its management. A step-up, minimally invasive drainage/debridement is the preferred approach for patients with infected pancreatic necrosis.

Plasma D-Dimer Level Is an Early Predictor of Severity of Acute Pancreatitis Based on 2012 Atlanta Classification

Background

Acute pancreatitis (AP) is a common digestive disorder. Its management depends on the severity; therefore, it is essential to stratify AP patients early. D-dimer, a coagulation indicator, appears to be associated with the pathogenesis of AP. The aim of this study was to evaluate D-dimer as an early predictor of the severity of AP.

Material/Methods

This was a single-center retrospective study of 1260 patients diagnosed based on the revised Atlanta classification. Only patients hospitalized within 24 h of onset were included, and 334 patients were enrolled. Blood was collected at admission and 3 times within 48 h of admission. Values at admission and average of the 3 blood samples were evaluated by univariate and multivariate analyses. Furthermore, the area under the receiver-operating characteristic curve (AUC) was used to estimate the validity of the predictor and to define optimal cut-off points for prediction.

Results

We found that 53.3% of the patients had mild AP (MAP), 24.3% had moderately severe AP (MSAP), and 22.4% had severe AP (SAP). D-dimer at admission and the average D-dimer could distinguish MAP patients from MSAP and SAP patients, with cut-off values of 3.355 mg/L and 4.868 mg/L, respectively. No difference in the parameters at admission was observed in multivariate analysis in distinguishing SAP from MSAP, but the average D-dimer level was significantly different with a cut-off value of 7.268 mg/L by comparing Ranson score, APACHE II score, and D-dimer level.

Conclusions

The average value of D-dimer levels could be used as a predictor of severity of AP. In general, patients with an average D-dimer level <4.868 could be diagnosed with MAP, >7.268 would develop into SAP, and between 4.868 and 7.268 would be MSAP.

Serum resistin: A possible link between inflammation, hypertension and coronary artery disease

Background & Objectives

Inflammation is considered as the main triggering factor in evolution of atherosclerotic pathology of heart and blood vessels. Resistin, an inflammatory cytokine is proved to be a main mediator of initiation and progression of mechanisms leading to atherosclerosis, hypertension and ultimately to coronary artery disease. Our objective was to compare the levels of serum resistin, C-reactive protein and total leucocyte count in subjects of hypertension and coronary artery disease; and to observe the correlation of serum resistin with CRP and TLC in the study participants.

Methods

Eighty selected participants were divided into four equal groups including normal healthy participants, newly diagnosed cases of hypertension, stable angina pectoris and myocardial infarction, both with hypertension. The study was conducted in the physiology department of Post Graduate Medical Institute Lahore, during 2013. After consent, history and examination, fasting blood samples of the participants were collected. Serum resistin and C-reactive protein were determined by using standard techniques of enzyme linked immunosorbent assay, while total leukocyte count by automated hematology analyzer.

Results

The values of serum resistin, C- reactive protein and total leukocyte count were found significantly raised in patients of hypertension, angina pectoris and myocardial infarction with hypertension as compared to normal participants (p<0.001 for all). Significantly positive correlation of resistin was observed with TLC only in hypertensive patients of myocardial infarction (r = 0.459, n = 20, p = 0.042) while in other study groups correlation between resistin and TLC as well as CRP was non-significant.

Conclusion

Serum resistin levels along with CRP and TLC are significantly raised in patients of hypertension and coronary artery disease while resistin levels revealed significantly positive correlation with TLC in hypertensive patients of myocardial infarction.

2019 WSES guidelines for the management of severe acute pancreatitis

Although most patients with acute pancreatitis have the mild form of the disease, about 20-30% develops a severe form, often associated with single or multiple organ dysfunction requiring intensive care. Identifying the severe form early is one of the major challenges in managing severe acute pancreatitis. Infection of the pancreatic and peripancreatic necrosis occurs in about 20-40% of patients with severe acute pancreatitis, and is associated with worsening organ dysfunctions. While most patients with sterile necrosis can be managed nonoperatively, patients with infected necrosis usually require an intervention that can be percutaneous, endoscopic, or open surgical. These guidelines present evidence-based international consensus statements on the management of severe acute pancreatitis from collaboration of a panel of experts meeting during the World Congress of Emergency Surgery in June 27-30, 2018 in Bertinoro, Italy. The main topics of these guidelines fall under the following topics: Diagnosis, Antibiotic treatment, Management in the Intensive Care Unit, Surgical and operative management, and Open abdomen.

Resistin as a Prooxidant Factor and Predictor of Endothelium Damage in Patients with Mild Acute Pancreatitis Exposed to Tobacco Smoke Xenobiotics

Objectives

The study was aimed to assess the influence of tobacco smoke exposure on the intensity of inflammation measured by IL-6, α₁-antitripsin (AAT) and α₁-acid glycoprotein (AGP) concentrations, and Cd level and oxidative stress intensity measured by advanced oxidation protein product (AOPP) concentration in the blood of healthy subjects and AP patients during hospitalization. Endothelin-1 (ET-1) and resistin concentrations, markers of endothelium injury, were determined.

Results

An increased IL-6 concentration in healthy smokers compared to nonsmokers and AP patients compared to controls was shown. An increased AAT and AGP concentrations during hospitalization of AP patients were noted, in both smokers (AAT, AGP) and nonsmokers (AAT). In comparison to control groups, in AP patients, a 2-fold increased resistin concentration correlating with ET-1 concentration and decreased albumin concentration accompanied by increased AOPP concentration were demonstrated. AOPP concentration was higher in smokers with AP compared to nonsmokers and gradually enhanced during their hospitalization.

Conclusions

Tobacco smoke exposure can have a proinflammatory effect in both healthy subjects and AP patients. Increased resistin concentration in AP patients negatively correlating with albumin concentration has prooxidative effect on this protein resulting in enhanced AOPP level. Increased resistin concentration can intensify AAT and AGP production during AP.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.

Serum C-reactive protein, procalcitonin, and lactate dehydrogenase for the diagnosis of pancreatic necrosis

BACKGROUND

The treatment of people with pancreatic necrosis differs from that of people with oedematous pancreatitis. It is important to know the diagnostic accuracy of serum C-reactive protein (CRP), serum procalcitonin, and serum lactate dehydrogenase (LDH) as a triage test for the detection of pancreatic necrosis in people with acute pancreatitis, so that an informed decision can be made as to whether the person with pancreatic necrosis needs further investigations such as computed tomography (CT) scan or magnetic resonance imaging (MRI) scan and treatment for pancreatic necrosis started. There is currently no standard clinical practice, although CRP, particularly an increasing trend of CRP, is often used as a triage test to determine whether the person requires further imaging. There is also currently no systematic review of the diagnostic test accuracy of CRP, procalcitonin, and LDH for the diagnosis of pancreatic necrosis in people with acute pancreatitis.

OBJECTIVES

To compare the diagnostic accuracy of CRP, procalcitonin, or LDH (index test), either alone or in combination, in the diagnosis of necrotising pancreatitis in people with acute pancreatitis and without organ failure.

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, National Institute for Health Research (NIHR HTA and DARE), and other databases until March 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase.

SELECTION CRITERIA

We included all studies that evaluated the diagnostic test accuracy of CRP, procalcitonin, and LDH for the diagnosis of pancreatic necrosis in people with acute pancreatitis using the following reference standards, either alone or in combination: radiological features of pancreatic necrosis (contrast-enhanced CT or MRI), surgeon's judgement of pancreatic necrosis during surgery, or histological confirmation of pancreatic necrosis. Had we found case-control studies, we planned to exclude them because they are prone to bias; however, we did not locate any. Two review authors independently identified the relevant studies from the retrieved references.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, including methodological quality assessment, from the included studies. As the included studies reported CRP, procalcitonin, and LDH on different days of admission and measured at different cut-off levels, it was not possible to perform a meta-analysis using the bivariate model as planned. We have reported the sensitivity, specificity, post-test probability of a positive and negative index test along with 95% confidence interval (CI) on each of the different days of admission and measured at different cut-off levels.

MAIN RESULTS

A total of three studies including 242 participants met the inclusion criteria for this review. One study reported the diagnostic performance of CRP for two threshold levels (> 200 mg/L and > 279 mg/L) without stating the day on which the CRP was measured. One study reported the diagnostic performance of procalcitonin on day 1 (1 day after admission) using a threshold level of 0.5 ng/mL. One study reported the diagnostic performance of CRP on day 3 (3 days after admission) using a threshold level of 140 mg/L and LDH on day 5 (5 days after admission) using a threshold level of 290 U/L. The sensitivities and specificities varied: the point estimate of the sensitivities ranged from 0.72 to 0.88, while the point estimate of the specificities ranged from 0.75 to 1.00 for the different index tests on different days of hospital admission. However, the confidence intervals were wide: confidence intervals of sensitivities ranged from 0.51 to 0.97, while those of specificities ranged from 0.18 to 1.00 for the different tests on different days of hospital admission. Overall, none of the tests assessed in this review were sufficiently accurate to suggest that they could be useful in clinical practice.

AUTHORS' CONCLUSIONS

The paucity of data and methodological deficiencies in the studies meant that it was not possible to arrive at any conclusions regarding the diagnostic test accuracy of the index test because of the uncertainty of the results. Further well-designed diagnostic test accuracy studies with prespecified index test thresholds of CRP, procalcitonin, LDH; appropriate follow-up (for at least two weeks to ensure that the person does not have pancreatic necrosis, as early scans may not indicate pancreatic necrosis); and clearly defined reference standards (of surgical or radiological confirmation of pancreatic necrosis) are important to reliably determine the diagnostic accuracy of CRP, procalcitonin, and LDH.