Pancreatic QST Differentiates Chronic Pancreatitis Patients into Distinct Pain Phenotypes Independent of Psychiatric Comorbidities

Somatosensory profiling to differentiate distinct painful diseases of the pancreas-a quantitative sensory testing case-control study

ABSTRACT

Mechanisms of pancreatic pain are insufficiently understood, and quantitative sensory testing (QST) may help to identify the underlying mechanisms. Accordingly, this study assessed comprehensive somatosensory profiles encompassing nociceptive and nonnociceptive parameters in 70 patients with distinct pancreatic diseases, namely acute (n = 23), chronic (n = 20), or autoimmune pancreatitis (n = 10) and pancreatic cancer (n = 17) and compared it with 30 healthy control subjects by standardized QST (protocol of the German research network on neuropathic pain). Patients with pancreatic diseases presented significant somatosensory deficits in all thermal and tactile detection and pain thresholds in the pancreatic viscerotome (Th10), when compared with a remote control area (dermatome C5) or reference data of matched healthy controls (P < 0.05-P < 0.0001). Unaltered vibration detection emphasizes the strictly regional character of losses. Loss of sensitivity paralleled the occurrence of paradoxical heat sensation (Th10 vs C5; P < 0.05), an indicator of thermal integration deficit. Punctate hyperalgesia or pain to light touch, the hallmark signs of spinal central sensitization were mostly absent and pain summation remained unchanged (P > 0.05). Stratification of patients revealed that somatosensory deficits were significantly more pronounced in acute compared with chronic pancreatitis (eg, cold and warm detection thresholds: -2.19 ± 1.42 vs -1.10 ± 1.23 and -1.30 ± 1.68 vs -0.11 ± 1.80 z-values; P < 0.05 each). Notably, blunt pressure hyperalgesia, the only somatosensory parameter exhibiting significant gain compared with the patients' remote C5 segment, was a frequent finding only in acute, but not in chronic pancreatitis. The somatosensory phenotype of patients with distinct pancreatic disorders was characterized by a wide array of sensory losses being most severe in acute pancreatitis.

16. Pain in chronic pancreatitis

INTRODUCTION

Chronic pancreatitis is defined as a disease of the pancreas in which recurrent inflammatory episodes result in replacement of the pancreatic parenchyma by fibrous connective tissue in individuals with genetic, environmental, and other risk factors. Pain is one of the most important symptoms of chronic pancreatitis and, in many cases, has chronic visceral nociceptive, nociplastic, and even neuropathic components, with evidence of both central and peripheral sensitization, neuroplasticity, and neurogenic inflammation.

METHODS

The literature on the diagnosis and treatment of pain in chronic pancreatitis was reviewed and summarized.

RESULTS

Treatment of abdominal pain in chronic pancreatitis is guided by pancreatic morphology on imaging, although the correlation between pain symptoms and pathoanatomical changes is not always straightforward. Patients with pancreatic duct obstruction are initially offered endoscopic or surgical therapies, while non-obstructive disease is mostly managed medically. Lifestyle changes and psychological support are of particular importance for all chronic pancreatitis patients. Analgesic options range from non-opioid medications to opioids and adjuvant agents. Interventional pain management may consist of radiofrequency treatment of the splanchnic nerves and spinal cord stimulation. To date, there are no randomized trials supporting their efficacy in the treatment of chronic pancreatitis pain, and the recommendation to consider these treatment options is justified by evidence from observational studies. Possible opioid-sparing effects of interventional pain treatments are important to consider because opioid use and dependency are common in chronic pancreatitis patients and associated with worse outcomes. Celiac plexus block is not generally recommended for chronic pancreatitis due to the limited quality of evidence, overall short duration of effect, and invasiveness of the procedure. Central sensitization can impact the effectiveness of invasive treatments.

CONCLUSIONS

Managing pain in chronic pancreatitis is a complex task that requires a multidimensional and individualized approach. Due to the lack of randomized trials, treatment decisions are often guided by expert opinion. Integrating pharmacological and non-pharmacological interventions and collaborating with a multidisciplinary team are key components of effective chronic pancreatitis pain management.

Pathophysiology, Assessment, and Management of Pain Associated with Chronic Pancreatitis

Chronic pancreatitis (CP) is a fibroinflammatory disease, with pain as its most prominent symptom. This article provides a comprehensive review of the pathophysiology, assessment methodologies, and management strategies pertaining to pain in CP. Pathophysiological mechanisms include inflammatory and neuropathic components, including peripheral and central sensitization. Pain assessment can include unidimensional and multidimensional pain assessment scales, neurophysiological assessments, and advanced imaging techniques. Management strategies include a spectrum from lifestyle modifications, pharmacologic interventions, and interventional procedures to neuromodulatory techniques and other experimental treatments.

Heterogeneity in Pancreatitis: Recognizing Heterogeneity and Its Role in the Management of Pancreatitis Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

ABSTRACT

Both the clinical management and study of recurrent acute pancreatitis and chronic pancreatitis are complicated by significant heterogeneity in the etiology, mechanisms, symptoms, and complications of pancreatitis. The National Institutes of Diabetes and Digestive and Kidney Disease recently convened a workshop to address current knowledge and knowledge gaps in the field. Preclinical models that better replicate human disease are important for development of new therapies. Pain is often the most common and most difficult symptom to treat, as the causes are multifactorial and effective treatment may vary depending on whether pain is neuropathic or nociceptive in origin, and the placebo effect can complicate evaluation of the efficacy of medical and procedural interventions. Novel technologies like functional magnetic resonance imaging and virtual reality may offer novel means for assessing and treating pain, respectively. Clinical trial designs will need to consider best approaches to addressing the heterogeneity of chronic pancreatitis, including careful attention to designing eligibility criteria, and establishing accepted and validated core outcomes criteria for the field. The latter may be informed by consensus in pain research. Recruitment of participants into clinical trials has been challenging, often requiring multiple centers. Establishment of a clinical trials network would facilitate greater opportunities for therapeutic trials in pancreatitis.

Genetics of constant and severe pain in the NAPS2 cohort of recurrent acute and chronic pancreatitis patients

Recurrent acute and chronic pancreatitis (RAP, CP) are complex, progressive inflammatory diseases with variable pain experiences impacting patient function and quality of life. The genetic variants and pain pathways in patients contributing to most severe pain experiences are unknown. We used previously genotyped individuals with RAP/CP from the North American Pancreatitis Study II (NAPS2) of European Ancestry for nested genome-wide associated study (GWAS) for pain-severity, chronicity, or both. Lead variants from GWAS were determined using FUMA. Loci with p<1e-5 were identified for post-hoc candidate identification. Transcriptome-wide association studies (TWAS) identified loci in cis and trans to the lead variants. Serum from phenotyped individuals with CP from the PROspective Evaluation of Chronic Pancreatitis for EpidEmiologic and Translational StuDies (PROCEED) was assessed for BDNF levels using Meso Scale Discovery Immunoassay. We identified four pain systems defined by candidate genes: 1) Pancreas-associated injury/stress mitigation genes include: REG gene cluster, CTRC, NEURL3 and HSF22. 2) Neural development and axon guidance tracing genes include: SNPO, RGMA, MAML1 and DOK6 (part of the RET complex). 3) Genes linked to psychiatric stress disorders include TMEM65, RBFOX1, and ZNF385D. 4) Genes in the dorsal horn pain-modulating BDNF/neuropathic pathway included SYNPR, NTF3 and RBFOX1. In an independent cohort BDNF was significantly elevated in patients with constant-severe pain. Extension and expansion of this exploratory study may identify pathway- and mechanism-dependent targets for individualized pain treatments in CP patients. PERSPECTIVE: Pain is the most distressing and debilitating feature of chronic pancreatitis. Yet many patients with chronic pancreatitis have little or no pain. The North American Pancreatitis Study II (NAPS2) includes over 1250 pancreatitis patients of all progressive stages with all clinical and phenotypic characteristics carefully recorded. Pain did not correlate well with disease stage, inflammation, fibrosis or other features. Here we spit the patients into groups with the most severe pain and/or chronic pain syndromes and compared them genetically with patients reporting mild or minimal pain. Although some genetic variants associated with pain were expressed in cells (1) of the pancreas, most genetic variants were linked to genes expressed in the nervous system cells associated with (2) neural development and axon guidance (as needed for the descending inhibition pathway), (3) psychiatric stress disorders, and (4) cells regulating sensory nerves associated with BDNF and neuropathic pain. Similar and overlapping genetic variants in systems 2 -4 are also seen in pain syndromes form other organs. The implications for treating pancreatic pain are great in that we can no longer focus on just the pancreas. Furthermore, new treatments designed for pain disorders in other tissues may be effective in some patient with pain syndromes from the pancreas. Further research is needed to replicate and extend these observations so that new, genetics-guided rational treatments can be developed and delivered.

Individualized Pain Treatment in Chronic Pancreatitis (INPAIN): An International, Multicenter, Investigator-Initiated, Prospective, Cohort Study

OBJECTIVES

Pain is the foremost complication of chronic pancreatitis (CP), affecting about 70% of patients. However, the pathophysiological understanding and management of CP-related pain are complex, likely as patients have diverse "pain phenotypes" responding differently to treatment. This study aims to develop a bedside test panel to identify distinct pain phenotypes, investigate the temporal evolution, and determine whether they can be used to predict treatment response.

METHODS

The INPAIN study is an international, multicenter, observational, longitudinal cohort study consisted of 4 substudies. The studies will prospectively enroll 400 CP patients (50 without pain and 350 with pain) and 50 control subjects, conducting biannual observations for 4 years. The test panel is consisted of comprehensive subjective and objective assessment parameters. Statistical analysis strategies differ across the substudies. A model to predict treatment efficacy will be developed using various machine learning techniques, including an artificial intelligence approach, with internal cross-validation. Trajectories in pain parameters will be characterized by graphical analysis and mixed effect models.

DISCUSSION

The INPAIN study aims to comprehensively understand pain in CP through a test panel developed for routine clinical use. This tool has the potential to personalize treatments, improve clinical practice, enhance patient care, improve quality of life, and minimize treatment side effects.

Pancreatitis in children: practical management from the BSPGHAN Pancreatitis Working Group

Pancreatitis, a condition characterised by inflammation of the pancreas, has multiple aetiologies. Improving clinical proficiency in prompt diagnosis and effective management leads to better outcomes for children with acute pancreatitis, acute recurrent pancreatitis and chronic pancreatitis. Establishing consensus guidance via the British Society of Paediatric Gastroenterology Hepatology and Nutrition Pancreatitis Working Group has ensured further focus on these patients who are often cared for in a multidisciplinary framework and may prompt future research in this area. Initial assessment includes serum amylase/lipase, triglyceride levels, full blood count, C reactive protein, renal and liver function profile, glucose, calcium and capillary blood gas. Fasted transabdominal ultrasound for all children and young people with suspected pancreatitis is recommended to identify pancreatic parenchyma and pancreatobiliary ductal changes, and complications. For fluid resuscitation, use crystalloids or Ringer’s lactate: initial bolus of 10 to 20 mL/kg, 1.5–2 times maintenance volume, with hourly monitoring of urine output over the initial 24–48 hours. Initiate oral intake within the first 24 hours after fluid resuscitation; fat restriction is not recommended. For suspected autoimmune pancreatitis, workup includes immunoglobulin levels (IgG, IgM, IgA, IgG subclasses), complement components and autoantibody profile to confirm diagnosis. Significant interventional management for pancreatitis and related complications is performed via endoscopic retrograde cholangiopancreatography or endoscopic ultrasound; referral to a specialised paediatric hepatobiliary surgical team is highly recommended. Close collaboration with a specialist centre can improve diagnostic and management pathways and outcomes for children.

A sham-controlled, randomized trial of spinal cord stimulation for the treatment of pain in chronic pancreatitis

BACKGROUND

Spinal cord stimulation (SCS) has emerged as a treatment option for patients with chronic pancreatitis (CP) who experience pain that does not respond to standard interventions. However, there is a lack of sham-controlled trials to support its efficacy.

METHODS

This randomized, double-blinded, sham-controlled, cross-over trial enrolled 16 CP patients with insufficient pain relief from standard therapies. Patients underwent high-frequency (1000 Hz) paraesthesia-free SCS or sham for two 10-day stimulation periods, separated by a 3-day washout period. The primary outcome was daily pain intensity registered in a pain diary based on a numeric rating scale (NRS). Secondary outcomes included various questionnaires. Quantitative sensory testing was used to probe the pain system before and after interventions.

RESULTS

The average daily pain score on the NRS at baseline was 5.2 ± 1.9. After SCS, the pain score was 4.2 ± 2.1 compared to 4.3 ± 2.1 in the sham group (mean difference -0.1, 95% CI [-1.4 to 1.1]; P = 0.81). Similarly, no differences were observed between groups for the maximal daily pain score, secondary outcomes or quantitative sensory testing parameters. During an open-label, non-sham-controlled and non-blinded extension of the study, the average daily NRS was 5.2 ± 1.7 at baseline, 3.2 ± 1.8 at 3 months, 2.9 ± 1.9 at 6 months and 3.4 ± 2.2 at 12 months of follow-up (P = 0.001).

CONCLUSION

In this first sham-controlled trial of SCS in painful CP, we did not find evidence of short-term pain relief with paraesthesia-free high-frequency (1000 Hz) stimulation. However, evaluation of the long-term effect by larger sham-controlled trials with long-term follow-up is warranted.

SIGNIFICANCE STATEMENT

In this first sham-controlled trial to apply high-frequency (1000 Hz) spinal cord stimulation in patients with visceral pain due to chronic pancreatitis, we did not find evidence for clinically relevant pain relief. Taken together with potential procedure-related complications, adverse effects and costs associated with spinal cord stimulation, our findings question its use for management of visceral pain.

Clinical characterization of the silent chronic pancreatitis patient: a single-center retrospective cohort study

Background

Silent chronic pancreatitis (SCP) is a poorly understood subtype of chronic pancreatitis (CP) in which individuals describe little to no abdominal pain. The risk factors for SCP are unclear, and it is unknown whether there are differences in the clinical outcomes of SCP and painful CP. We set out to investigate the clinical features of SCP and the risk factors associated with this condition.

Methods

This was a retrospective cohort study using data from the Penn State Milton S. Hershey Medical Center from 2019-2022. Two patient groups, the SCP cohort (23 patients) and the painful CP cohort (94 patients), were identified from consecutive clinics. Descriptive statistics and bivariate and logistic regression analyses (including variables with a P-value <0.1 on bivariate analysis) were performed to characterize the study cohort and to evaluate for independent associations with SCP.

Results

SCP was independently associated with older age (odds ratio [OR] 1.06, 95% confidence interval [CI] 1.01-1.11; P=0.03) and male sex (OR 5.38, 95%CI 1.38-20.96; P=0.02), and inversely associated with current opioid use (OR 0.18, 95%CI 0.03-0.96; P=0.04). There was no association between SCP and current pain medication or diabetes mellitus.

Conclusions

Our study adds to the growing body of literature describing SCP as a condition associated with older age and male sex, and inversely associated with opioid use. We found no greater association of diabetes with SCP. Future larger longitudinal studies are needed to gain a better understanding of SCP.

A Randomized Controlled Phase 2 Dose-Finding Trial to Evaluate the Efficacy and Safety of Camostat in the Treatment of Painful Chronic Pancreatitis: The TACTIC Study

BACKGROUND & AIMS

Chronic pancreatitis (CP) causes an abdominal pain syndrome associated with poor quality of life. We conducted a clinical trial to further investigate the efficacy and safety of camostat, an oral serine protease inhibitor that has been used to alleviate pain in CP.

METHODS

This was a double-blind randomized controlled trial that enrolled adults with CP with a baseline average daily worst pain score ≥4 on a numeric rating system. Participants were randomized (1:1:1:1) to receive camostat at 100, 200, or 300 mg 3 times daily or placebo. The primary end point was a 4-week change from baseline in the mean daily worst pain intensity score (0-10 on a numeric rating system) using a mixed model repeated measure analysis. Secondary end points included changes in alternate pain end points, quality of life, and safety.

RESULTS

A total of 264 participants with CP were randomized. Changes in pain from baseline were similar between the camostat groups and placebo, with differences of least squares means of -0.11 (95% CI, -0.90 to 0.68), -0.04 (95% CI, -0.85 to 0.78), and -0.11 (95% CI, -0.94 to 0.73) for the 100 mg, 200 mg, and 300 mg groups, respectively. Multiple subgroup analyses were similar for the primary end point, and no differences were observed in any of the secondary end points. Treatment-emergent adverse events attributed to the study drug were identified in 42 participants (16.0%).

CONCLUSION

We were not able to reject the null hypothesis of no difference in improvements in pain or quality of life outcomes in participants with painful CP who received camostat compared with placebo. Studies are needed to further define mechanisms of pain in CP to guide future clinical trials, including minimizing placebo responses and selecting targeted therapies.

CLINICALTRIALS

gov, Number: NCT02693093.

Pancreatic quantitative sensory testing to predict treatment response of endoscopic therapy or surgery for painful chronic pancreatitis with pancreatic duct obstruction: study protocol for an observational clinical trial

INTRODUCTION

Treatment for abdominal pain in patients with chronic pancreatitis (CP) remains challenging in the setting of central nervous system sensitisation, a phenomenon of remodelling and neuronal hyperexcitability resulting from persistent pain stimuli. This is suspected to render affected individuals less likely to respond to conventional therapies. Endotherapy or surgical decompression is offered to patients with pancreatic duct obstruction. However, the response to treatment is unpredictable. Pancreatic quantitative sensory testing (P-QST), an investigative technique of standardised stimulations to test the pain system in CP, has been used for phenotyping patients into three mutually exclusive groups: no central sensitisation, segmental sensitisation (pancreatic viscerotome) and widespread hyperalgesia suggestive of supraspinal central sensitisation. We will test the predictive capability of the pretreatment P-QST phenotype to predict the likelihood of pain improvement following invasive treatment for painful CP.

METHODS AND ANALYSIS

This observational clinical trial will enrol 150 patients from the University of Pittsburgh, Johns Hopkins and Indiana University. Participants will undergo pretreatment phenotyping with P-QST. Treatment will be pancreatic endotherapy or surgery for clearance of painful pancreatic duct obstruction.

PRIMARY OUTCOME

average pain score over the preceding 7 days measured by Numeric Rating Scale at 6 months postintervention. Secondary outcomes will include changes in opioid use during follow-up, and patient-reported outcomes in pain and quality of life at 3, 6 and 12 months after the intervention. Exploratory outcomes will include creation of a model for individualised prediction of response to invasive treatment.

ETHICS AND DISSEMINATION

The trial will evaluate the ability of P-QST to predict response to invasive treatment for painful CP and develop a predictive model for individualised prediction of treatment response for widespread use. This trial was approved by the University of Pittsburgh Institutional Review Board. Data and results will be reported and disseminated in conjunction with National Institutes of Health policies.

TRIAL REGISTRATION NUMBER

NCT04996628.

Recent advances in the understanding and management of chronic pancreatitis pain

Abdominal pain is the most common symptom of chronic pancreatitis (CP) and is often debilitating for patients and very difficult to treat. To date, there exists no cure for the disease. Treatment strategies focus on symptom management and on mitigation of disease progression by reducing toxin exposure and avoiding recurrent inflammatory events. Traditional treatment protocols start with medical management followed by consideration of procedural or surgical intervention on selected patients with severe and persistent pain. The incorporation of adjuvant therapies to treat comorbidities including psychiatric disorders, exocrine pancreatic insufficiency, mineral bone disease, frailty, and malnutrition, are in its early stages. Recent clinical studies and animal models have been designed to improve investigation into the pathophysiology of CP pain, as well as to improve pain management. Despite the array of tools available, many therapeutic options for the management of CP pain provide incomplete relief. There still remains much to discover about the neural regulation of pancreas-related pain. In this review, we will discuss research from the last 5 years that has provided new insights into novel methods of pain phenotyping and the pathophysiology of CP pain. These discoveries have led to improvements in patient selection for optimization of outcomes for both medical and procedural management, and identification of potential future therapies.

Advances in the Management of Pain in Chronic Pancreatitis

PURPOSE OF REVIEW

The data on recent advances in managing chronic pancreatitis (CP) pain is limited. This review highlights the role of endotherapy and the advances in the overall management of pain in CP.

RECENT FINDINGS

Of late, pancreatic biodegradable stents have been used in endotherapy with appreciable success. These include slow, medium, and fast degrading stents, which optimize the overall management of CP and could prevent the need for multiple procedures. Endoscopic ultrasound-guided celiac plexus block is reserved in selected patients to treat debilitating pain. Total pancreatectomy with islet autotransplantation in small duct disease has shown promising results. The indications for treating pain in CP with endoscopy and surgery need to be better defined. The complexity of pain control due to the incomplete understanding of pathomorphology makes the management of CP challenging. The current treatment methods are still evolving. Therapy aims to reduce pain, optimize recovery, maintain quality of life, and meet postoperative needs. Initial management includes lifestyle modification, nutrition optimization, risk factor reduction with abstinence from alcohol, cessation of tobacco and smoking. Supportive medical management involves the judicial use of analgesics, neuromodulators, antioxidants, pancreatic enzyme replacement for insufficiency, and diabetes management. Patients with intractable pain are ideal for therapeutic intervention. Being less invasive with an acceptable complication rate makes endotherapy the preferred first-line treatment. If found to be cost-effective, biodegradable stents can reduce the overall cost. Unfortunately, if patients remain symptomatic, surgery is preferred in case of failure or recurrence. For optimal results, appropriate patient selection is vital to maximizing outcomes.

Spinal Excitability in Patients with Painful Chronic Pancreatitis

Purpose

Abdominal pain is common in patients with chronic pancreatitis (CP), but management is challenging - possibly due to altered pain processing within the central nervous system rendering conventional treatments ineffective. We hypothesized that many patients with painful CP have generalized hyperalgesia correlating with central neuronal hyperexcitability.

Patients and Methods

Seventeen CP patients with pain and 20 matched healthy controls underwent experimental pain testing, including repeated pain stimuli (temporal summation), pressure algometry performed in dermatomes with same spinal innervation as the pancreatic gland (pancreatic areas) and remote dermatomes (control areas), a cold pressor test and a conditioned pain modulation paradigm. To probe central neuronal excitability, the nociceptive withdrawal reflex was elicited by electrical stimulation of the plantar skin, and electromyography was obtained from the ipsilateral anterior tibial muscle together with somatosensory evoked brain potentials.

Results

Compared to healthy controls, patients with painful CP had generalized hyperalgesia as evidenced by 45% lower pressure pain detection thresholds (P<0.05) and decreased cold pressor endurance time (120 vs 180 seconds, P<0.001). In patients, reflex thresholds were lower (14 vs 23 mA, P=0.02), and electromyographic responses were increased (16.4 vs 9.7, P=0.04) during the withdrawal reflex, reflecting predominantly spinal hyperexcitability. Evoked brain potentials did not differ between groups. A positive correlation was found between reflex thresholds and cold pressor endurance time (ρ=0.71, P=0.004).

Conclusion

We demonstrated somatic hyperalgesia in patients with painful CP associated with spinal hyperexcitability. This highlights that management should be directed at central mechanisms using, eg, gabapentinoids or serotonin-noradrenaline reuptake inhibitors.

Quality of Life and Pain in Patients With Chronic Pancreatitis

INTRODUCTION

The quality of life (QoL) of patients with chronic conditions is a function of factors associated with the illness, its natural course, and treatment as well as those related to the patient. Chronic pancreatitis (CP) is a critical public health problem. Chronic pancreatitis patients can experience chronic pain with different mechanisms, malabsorption, diabetes, and cachexia.

OBJECTIVE

Chronic pancreatitis (CP) is a critical public health problem. CP patients can experience chronic pain with different mechanisms, malabsorption, diabetes, and cachexia. The aim of the study was to assess the Quality of Life (QoL) of patients with CP and identify factors affecting QoL.

METHODS

104 patients diagnosed with CP from the hospital in Wrocław, Poland, were included. The study was conducted using our own questionnaire, the World Health Organization Quality of Life-BREF (WHOQOL-BREF) scale, the 36-Item Short Form Health Survey (SF-36), and the Visual Analog Scale (VAS).

RESULTS

The mean total SF-36 score was 47.7, with the highest mean rating for the physical functioning domain. The mean VAS pain score was 5.13. Pain intensity was significantly correlated with impairments in activities of daily living (P = 0.001), the need to reduce their duration (P = 0.001), and the performance of physical activity (P = 0.003). Comorbidities, education, and age have a significant relationship with only some domains of SF-36.

CONCLUSIONS

One aspect that has an impact on QoL impairment is pain which perception is governed by the same brain regions in which abnormalities result in depression and anxiety. QoL in CP patients also depends on the patient's age, comorbidities, and level of education.

Chemical pancreatectomy in non-human primates ablates the acini and ducts and enhances beta-cell function

Chronic pancreatitis is a debilitating disease affecting millions worldwide. These patients suffer from bouts of severe pain that are minimally relieved by pain medications and may necessitate major surgeries with high morbidity and mortality. Previously, we demonstrated that "chemical pancreatectomy," a pancreatic intraductal infusion of dilute acetic acid solution, ablated the exocrine pancreas while preserving the endocrine pancreas. Notably, chemical pancreatectomy resolved chronic inflammation, alleviated allodynia in the cerulein pancreatitis model, and improved glucose homeostasis. Herein, we extensively tested the feasibility of a chemical pancreatectomy in NHPs and validated our previously published pilot study. We did serial computed tomography (CT) scans of the abdomen and pelvis, analyzed dorsal root ganglia, measured serum enzymes, and performed histological and ultrastructural assessments and pancreatic endocrine function assays. Based on serial CT scans, chemical pancreatectomy led to the loss of pancreatic volume. Immunohistochemistry and transmission electron microscopy demonstrated exocrine pancreatic ablation with endocrine islet preservation. Importantly, chemical pancreatectomy did not increase pro-nociceptive markers in harvested dorsal root ganglia. Also, chemical pancreatectomy improved insulin secretion to supranormal levels in vivo and in vitro. Thus, this study may provide a foundation for translating this procedure to patients with chronic pancreatitis or other conditions requiring a pancreatectomy.

Anxiety, depression, and coping styles among patients with chronic pancreatitis in East China

BACKGROUND

Anxiety and depression are common psychological comorbidities in patients with chronic pancreatitis (CP). There is still a lack of epidemiological studies on anxiety and depression in Chinese CP patients. This study aimed to identify the incidence and related factor of anxiety and depression among East Chinese CP patients and explore the relationship between anxiety, depression, and coping styles.

METHODS

This prospective observational study was conducted from June 1, 2019 to March 31, 2021 in Shanghai, China. Patient diagnosed with CP were interviewed using the sociodemographic and clinical characteristics questionnaire, Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), and Coping Style Questionnaire (CSQ). Multivariate logistic regression analysis was conducted to identify the related factors of anxiety and depression. Correlation test was preformed to analyze the correlation between anxiety, depression, and coping styles.

RESULTS

The incidence of anxiety and depression in East Chinese CP patients was 22.64% and 38.61%, respectively. Patients' previous health status, level of disease coping, frequency of abdominal pain episodes, and pain severity were significantly associated with anxiety and depression. Mature coping styles (Problem solving, Seeking for help) had a positive impact on anxiety and depression, while immature coping styles (Self-blame, Fantasy, Repression, Rationalization) had negative effects on anxiety and depression.

CONCLUSION

Anxiety and depression were common in patients with CP in China. The factors identified in this study may provide references for the management of anxiety and depression in CP patients.

Chemical pancreatectomy in non-human primates ablates the acini and ducts and enhances beta-cell function

Chronic pancreatitis is a debilitating disease affecting millions worldwide. These patients suffer from bouts of severe pain that are minimally relieved by pain medications and may necessitate major surgeries with high morbidity and mortality. Previously, we demonstrated that "chemical pancreatectomy," a pancreatic intraductal infusion of dilute acetic acid solution, ablated the exocrine pancreas while preserving the endocrine pancreas. Notably, chemical pancreatectomy resolved chronic inflammation, alleviated allodynia in the cerulein pancreatitis model, and improved glucose homeostasis. Herein, we extensively tested the feasibility of a chemical pancreatectomy in NHPs and validated our previously published pilot study. We did serial computed tomography (CT) scans of the abdomen and pelvis, analyzed dorsal root ganglia, measured serum enzymes, and performed histological and ultrastructural assessments and pancreatic endocrine function assays.  Based on serial CT scans, chemical pancreatectomy led to the loss of pancreatic volume. Immunohistochemistry and transmission electron microscopy demonstrated exocrine pancreatic ablation with endocrine islet preservation. Importantly, chemical pancreatectomy did not increase pro-nociceptive markers in harvested dorsal root ganglia. Also, chemical pancreatectomy improved insulin secretion to supranormal levels in vivo and in vitro. Thus, this study may provide a foundation for translating this procedure to patients with chronic pancreatitis or other conditions requiring a pancreatectomy.

Characterizing mechanism-based pain phenotypes in patients with chronic pancreatitis: a cross-sectional analysis of the PROspective Evaluation of Chronic Pancreatitis for EpidEmiologic and Translational StuDies

ABSTRACT

Pain is common in chronic pancreatitis (CP) and profoundly reduces quality of life (QoL). Multiple underlying mechanisms contribute to a heterogenous pain experience and reduce efficacy of pain management. This study was designed to characterize the distribution of mechanism-based pain phenotypes in painful CP. The data analyzed were collected as part of the PROspective Evaluation of Chronic Pancreatitis for EpidEmiologic and Translational StuDies, an NCI/NIDDK-funded longitudinal study of the natural history of CP. The PROspective Evaluation of Chronic pancreatitis for EpidEmiologic and translational stuDies includes patient-reported outcome (PRO) measures of pain, medication use, global health, and QoL. Of subjects (N = 681) with CP, 80% experienced abdominal pain within the year before enrollment. Subjects who experienced pain in the week before enrollment (N = 391) completed PROMIS Neuropathic and Nociceptive Pain Quality instruments which were then used to classify them by pain type: 40% had nociceptive, 5% had neuropathic-like, and 32% had both types of pain. The prevalence of having both types of pain was higher among women and subjects with diabetes mellitus, whereas nociceptive-only pain was more prevalent among men and those with pancreatic duct stricture. Other factors, including pain medication use and healthcare utilization, did not differ between groups based on pain type. Subjects in the Both group had significantly worse health and QoL scores relative to those with nociceptive-only pain, suggesting that using psychosocial pain surveys may be useful for understanding pain subtypes in patients with CP. Additional research is needed to identify biochemical and biophysical signatures that may associate with and predict responses to mechanism-specific interventions.

Natural history, clinical characteristics, outcomes, and long-term follow-up of pain-free chronic pancreatitis

Background

Chronic pancreatitis (CP) is characterized by chronic abdominal pain and functional insufficiency. However, a small subset of patients with prior acute pancreatitis (AP) and/or underlying risk factors for developing CP may be pain-free at diagnosis and may have a different clinical course. We aimed to compare the clinical characteristics, outcomes, and healthcare utilization between CP patients with and without pain.

Methods

Reviewed patients with established CP were followed in our Pancreas Center between January 2016 and April 2021. Patients without risk factors for developing CP and/or without AP prior to their diagnosis and only with incidental radiologic features of CP were excluded, so as to minimize confounding factors of pancreatopathy unrelated to CP. Patients were divided into painful and pain-free groups to analyze differences in demographics, outcomes, and healthcare utilization.

Results

Of 368 CP patients, 49 (13.3%) were pain-free at diagnosis and had remained so for >9 years. There were no significant differences in body mass index, race, sex, or co-morbidities between the two groups. Pain-free patients were older at diagnosis (53.9 vs 45.7, P = 0.004) and had less recurrent AP (RAP) (43.8% vs 72.5%, P < 0.001) and less exocrine pancreatic insufficiency (EPI) (34.7% vs 65.7%, P < 0.001). Pain-free patients had less disability (2.2% vs 22.0%, P = 0.003), mental illness (20.4% vs 61.0%, P < 0.001), surgery (0.0% vs 15.0%, P = 0.059), and therapeutic interventions (0.0% vs 16.4%, P = 0.005) for pain.

Conclusions

We described a unique subset of patients with underlying risk factors for CP and/or prior AP who were pain-free at diagnosis. They were older at diagnosis, had less EPI and RAP, and overall favorable outcomes with minimal resource utilization.

Somatosensory Profiles Differentiate Pain and Psychophysiological Symptoms Among Young Adults With Irritable Bowel Syndrome: A Cluster Analysis

OBJECTIVE

The aim of this study was to investigate if somatosensory profiles can differentiate pain and psychophysiological symptoms among young adults with irritable bowel syndrome (IBS).

METHODS

We performed a cluster analysis of data collected from a randomized clinical trial of 80 IBS patients and 21 age-matched healthy controls (HCs) to stratify pain and symptoms among young adults with IBS by their peripheral sensory profiles. Data of quantitative sensory testing and IBS-related pain and symptoms were collected at baseline and 6-week and 12-week follow-ups.

RESULTS

Using the K-means method, IBS patients were classified into 2 clusters, the "IBS normal threshold" (IBS-NT) and the "IBS increased threshold" (IBS-IT). The IBS-NT cluster had a similar pain threshold as the HCs, and the IBS-IT cluster had an increased threshold of somatic pain perception (lower cold pain threshold, higher heat pain threshold, and higher pressure pain threshold, all P<0.001) than HCs. Compared with the IBS-NT cluster, the IBS-IT cluster reported higher levels of IBS-related pain intensity, anxiety, fatigue, and sleep disturbance over the 3 visits (all P<0.05).

DISCUSSION

Young adults with IBS fell into 2 clusters, one with a similar sensory threshold as the HCs and another with an increased pain threshold, who reported higher pain intensity and more severe symptoms. Somatic sensory profiles should be integrated into further personalized self-management intervention among patients with IBS.

Pain Sensitivity and Psychiatric Comorbidities in Chronic Pancreatitis Patients With and Without Pain: Past Experience Matters

Background and Aims

Pain is the primary symptom of chronic pancreatitis (CP) and has been associated with abnormal pain processing and psychologic distress. Little is known about these phenomena in patients with painless disease. The aim of this study was to characterize patterns of pain processing and psychologic distress in patients with primary painless vs painful CP.

Methods

This was a cross-sectional multicenter study of 235 patients with definitive CP. Patients were categorized based on current and past pain history; current pain (79%), no current (but prior) pain (11%), and painless CP (10%). Demographic information and clinical data including symptoms of anxiety and depression using the Hospital Anxiety and Depression Scale were collected. All patients underwent quantitative sensory testing to assess patterns of pain processing.

Results

A total of 235 patients (57% males, mean age 53.9 ± 14.0 years, 41% alcohol etiology) were included. Compared to patients with painless CP, enhanced pain sensitivity was observed in both patients with current pain (odds ratio [OR] 3.29; 95% confidence interval [CI] [1.11-9.77], P = .032) and no current pain (OR 4.07; 95% CI [1.10-15.03], P = .035). Patients with current pain also had increased depression prevalence compared to patients with painless CP (OR 6.15; 95% CI [1.28-29.41], P = .023), while no difference was seen for patients with no current pain (OR 1.24; 95% CI [0.19-8.26], P = .824).

Conclusion

Total absence of pain in CP is associated with normal pain processing and low prevalence of psychologic distress, whereas patients with prior pain experience appear to have persistent and enhanced pain sensitivity even in the absence of clinical pain and psychologic distress.

Prevalence of primary painless chronic pancreatitis: A systematic review and meta-analysis

BACKGROUND/OBJECTIVES

While pain is the predominant symptom of chronic pancreatitis (CP), a subset of patients may experience a painless course. This systematic review aimed to determine the prevalence of primary painless CP.

METHODS

MEDLINE (PubMed), EMBASE and Web of Science Core Collection databases were searched for published studies through September 15, 2020 that included at least 10 consecutive patients with CP and which reported the number with painless CP. The presence of a history of recurrent acute pancreatitis (RAP), exocrine pancreatic insufficiency (EPI), diabetes mellitus (DM) and pancreatic adenocarcinoma (PA) in the painless CP patients was also recorded. A random effects model was used to determine pooled prevalence estimates with 95% confidence intervals (95% CI).

RESULTS

Among the 5057 studies identified and screened, 42 full-text articles were included in the final analysis. There were a total of 14,277 patients with CP among whom 1569 had painless CP. The pooled prevalence of painless CP was 12% (95% CI 10-15%). Among a subset of studies that reported on calcifications (n = 11), DM (n = 12), EPI (n = 8) and history of RAP (n = 14), the pooled prevalence estimates were 96% (95% CI 73-100%), 51% (95% CI 32-70%), and 47% (95% CI 15-81%), respectively. Alcohol, idiopathic/genetic and other etiologies were attributed to be the cause of painless CP in 32.4%, 56.9% and 8.9% patients, respectively.

CONCLUSION

Approximately one in ten patients with CP have primary painless disease with the majority being attributable to an idiopathic/genetic etiology. Further research is needed to determine the optimal management of these patients.

Assessment of pain associated with chronic pancreatitis: An international consensus guideline

Pain is the most common symptom in chronic pancreatitis (CP) with a major impact on quality of life. Few validated questionnaires to assess pain in CP exist, and the lack of consensus negatively impacts clinical management, research and meta-analysis. This guideline aims to review generic pain questionnaires for their usability in CP, to outline how pain assessment can be modified by confounding factors and pain types, to assess the value of additional measures such as quality of life, mental health and quantitative sensory testing, and finally to review pain assessment questionnaires used specifically in CP. A systematic review was done to answer 27 questions that followed the PICO (Population; Intervention; Comparator; Outcome) template. Quality of evidence of the statements was judged by Grades of Recommendation, Assessment, Development and Evaluation (GRADE) criteria. The manuscript was sent for review to 36 experts from various disciplines and continents in a multi-stage Delphi process, and finally reviewed by patient representatives. Main findings were that generic pain instruments are valid in most settings, but aspects of pain are specific for CP (including in children), and instruments have to account for the wide phenotypic variability and development of sensitization of the central nervous system. Side effects to treatment and placebo effects shall also be considered. Some multidimensional questionnaires are validated for CP and are recommended together with assessment of quality of life and psychiatric co-morbidities. This guideline will result in more homogeneous and comprehensive pain assessment to potentially improve management of painful CP.

Painful chronic pancreatitis - new approaches for evaluation and management

PURPOSE OF REVIEW

Management of abdominal pain in patients with chronic pancreatitis is often suboptimal. We review recent data on the epidemiology and new approaches for managing pain in chronic pancreatitis.

RECENT FINDINGS

Chronic pancreatitis duration does not appear to affect the pain experience. Pain pattern in chronic pancreatitis patients frequently changes and is not related to traditional patient and disease-related factors. Psychologic comorbidities, i.e. anxiety and depression, are frequent in patients with chronic pancreatitis, and are associated with more severe pain and pain interference. Adjunctive treatments, such as cognitive behavioral therapy, may positively influence pain management in chronic pancreatitis. Total pancreatectomy with islet autotransplantation (TPIAT) is an increasingly adopted treatment option in painful chronic pancreatitis. Ongoing multicenter studies will help define optimal candidates, predictors of successful pain remission and diabetes outcomes after TPIAT. Pancreatic quantitative sensory testing, a promising technique to interrogate nociception and sensory response, holds promise to identify patients with central sensitization. Initial studies show feasibility to stratify patients into defined pain profiles, and future studies will explore if these can help in prognostication of pain therapy.

SUMMARY

Several lines of investigations currently under evaluation are likely to have a positive impact on the management of pain in chronic pancreatitis.