Role of methionine containing antioxidant combination in the management of pain in chronic pancreatitis: a systematic review and meta-analysis

Pain management in chronic pancreatitis

Pain in chronic pancreatitis (CP) is difficult to manage. Many patients suffer from inadequate pain relief, completely incapacitating them in their daily activities. Historically, despite their well-known adverse effects, opioids have been the pillar of treatment regimens in painful CP. The management is now gradually evolving with a better understanding of the underlying pathophysiology of CP-related pain. Clinicians should follow a holistic approach to the management of CP-associated pain, which must involve lifestyle changes that are coupled with analgesic medications and other pain-relieving interventions. Furthermore, there is no easy cure for vanquishing CP-associated pain. Each patient must be evaluated on a case-by-case basis by a multidisciplinary team to decide which treatment option is best suited for that individual.

Optimizing nutrition in chronic pancreatitis

PURPOSE OF REVIEW

This review aims to discuss recent developments in the nutritional management in chronic pancreatitis.

RECENT FINDINGS

Nutritional assessment should be comprehensive and include dietary history, anthropometry, and biochemical nutritional parameters. Micronutrients should be evaluated at least yearly and dual-energy X-ray absorptiometry (DEXA) at every 2-yearly intervals. Studies on pancreatic enzyme replacement therapy (PERT) have primarily evaluated coefficient of fat excretion (CFA), coefficient of nitrogen excretion (CNA), and stool weight. Two RCTs, in which patients were treated with PERT for 7 days in a blinded manner and subsequently extended for 6-12 months in an open-label manner, showed improvement in nutritional parameters. However, two subsequent RCTs failed to show any benefit, and the most recent observational study demonstrated persistence of malnutrition even after PERT. The reason for the latter findings were nonadherence to PERT and poor oral intake of calories. Therefore, it is essential to educate the patients on adherence, counsel on taking high-protein, high-calorie diet, and supplement nutrients in those with inadequate oral intake. Other associated manifestations, such as diabetes and related complications, and anxiety/depression could also contribute to malnutrition directly or indirectly, and should, therefore, be adequately managed.

SUMMARY

Nutritional assessment should be performed meticulously. Nutritional therapy should not be restricted to only PERT and nutritional supplementation, but should also include dietary counselling and disease related education.

Efficacy and Predictors of Pain Response to Combined Antioxidants in Children with Chronic Pancreatitis

BACKGROUND

Pain is a major problem in 90% of patients with chronic pancreatitis (CP). Studies evaluating response to antioxidants (AO) are conflicting and no pediatric studies are available.

AIMS

To evaluate markers of oxidative stress (OS), and efficacy and predictors of response to AO in improving pain in children with CP.

METHODS

Antioxidants were given to CP children for 6 months. Subjects were assessed at baseline and post-therapy for pain and markers of OS [serum thiobarbituric acid reactive substances (TBARS), superoxide dismutase (S-SOD)] and antioxidant levels [vitamin C, selenium, total antioxidant capacity-ferric reducing ability of plasma (FRAP)]. Matched healthy controls were assessed for OS and antioxidant levels. Good response was defined as ≥ 50% reduction in number of painful days/month.

RESULTS

48 CP children (25 boys, age 13 years) and 14 controls were enrolled. 38/48 cases completed 6 months of therapy. CP cases had higher OS [TBARS (7.8 vs 5.2 nmol/mL; p < 0.001)] and lower antioxidant levels [FRAP (231 vs. 381.3 µmol/L; p = 0.003), vitamin C (0.646 vs. 0.780 mg/dL; p < 0.001)] than controls. Significant reduction in TBARS and S-SOD and increase in FRAP, vitamin C, and selenium occurred after 6 months. 10.5% cases had minor side effects. 26(68%) cases had a good response, with 9(24%) becoming pain-free. Subjects with severe ductal changes had lower median BMI (- 0.73 vs 0.10; p = 0.04) and responded less often than those with mild changes (17/29 vs 9/9; p = 0.036).

CONCLUSION

CP children have higher OS than healthy controls. Antioxidant therapy is safe. Pain response is seen in 68% cases, less often in patients with severe ductal changes.

Chemical repair of damaged leucine and tryptophane by thiophenols at close to diffusion-controlled rates: Mechanisms and kinetics

Thiophenols are chemical species with multiple desirable biological properties, including their primary and secondary antioxidant capacity. In this work, the repairing antioxidant activity of eight different thiophenols has been investigated for damaged leucine and tryptophane. The investigation was carried out employing quantum mechanical and transition state methods to calculate the thermodynamic and kinetic data of the reactions involved, while simulating the biological conditions at physiological pH and aqueous and lipidic medium. The analysis of the atomic charges and the spin densities at each of the points on the potential energy surface was the tool that allowed the elucidation of the reaction mechanisms through which thiophenols repair the oxidative damage caused to the amino acids leucine and tryptophan. It was found that thiophenols can repair leucine via a hydrogen atom transfer mechanism in a manner which is similar to the one used by glutathione to repair the carbon-centered radicals of guanosine. In addition, thiophenols can also restore tryptophane, a nitrogen-centered radical, via proton-coupled electron transfer and single electron transfer mechanisms. Moreover, both processes occur at close to diffusion-controlled rates.

Idiopathic chronic pancreatitis: Beyond antioxidants

Chronic pancreatitis (CP) is a complex disease associated with gene-gene or gene-environment interactions. The incidence of idiopathic CP has shown an increasing trend, withits phenotypeshaving changed considerably in the last two decades. The diseaseitself can be regulated before it reaches the stage of established CP; however, the etiopathogenesis underlying idiopathic CP remains to be established, making the condition difficult to cure. Unfortunately, there also remains a lack of consensus regarding the beneficial effects of antioxidant therapiesfor CP. It is known that antioxidant therapy does not reduce inflammatory and fibrotic cytokines, making it unlikely that they could modulate the disease process. Although antioxidants are safe, very few studies to date have reported the long-term beneficial effects in patients with CP. Thus, studies are being performed to identify drugs that can improve symptoms and alter the natural history of CP. Statins, with their numerous pleiotropic effects, may play a role in the treatment of CP, butin 2006, their use was found to be associated with the undesirable side effect of promoting pancreatitis. Latter studies showed favourable effects of statins in CP, highlighting the particular benefits of lipophilic statins, such as lovastatin and simvastatin, over the hydrophilic statins, such as rosuvastatin. Ultimately, studies to repurpose N-acetylcysteine as a CP therapy areyielding very promising results.

Efficacy of Pregabalin and Antioxidants Combination in Reducing Pain in Chronic Pancreatitis: A Double Blind Randomized Trial

BACKGROUND

In patients with chronic pancreatitis (CP), pain relief is a dilemma. Antioxidants with pregabalin therapy have been reported to be useful. Hence, this study was carried out to determine the efficacy of the combination of antioxidant and pregabalin therapy in reducing pain in patients with CP.

METHODS

This was a prospective, double blind, superiority, and randomized trial in patients with CP. The treatment group received pregabalin with antioxidants therapy for 8 weeks, and a similar placebo was administered to the controls. Primary outcome was to determine the change in maximum pain intensity assessed by visual analog scale (VAS) and Izbicki pain score. Secondary outcomes were the number of painful days, opioid and non-opioid requirements, improvement in quality of life, number of hospital admission, and overall patient satisfaction.

RESULTS

A total of 90 patients were randomized to 45 in each arm. Demographic profile and baseline pain score were comparable. Patients in treatment group when compared to placebo group had a significant reduction in pain intensity (VAS score 2 ± 0.8 vs. 1.3 ± 0.9; p = 0.007), non-opioid analgesic requirement in days (54.4±2.9 vs. 55.7±1.5; p = 0.014), and number of hospital admissions (0.2 ± 0.5 vs. 0.6 ± 0.7; p = 0.002), respectively. Significant proportion of patients was satisfied in the treatment group compared to placebo group (18% vs. 11%; p = 0.03).

CONCLUSION

The combination of pregabalin and antioxidant significantly reduces the pain, requirement of non-opioid analgesics, and the number of hospital admissions in patients with CP. It also significantly improves the overall patient satisfaction.

CLINICAL TRIALS REGISTER NUMBER

CTRI/2017/05/008492.

Chronic Pancreatitis: Epidemiology, Diagnosis, and Management Updates

Chronic pancreatitis is a clinical entity that results from the progressive inflammation and irreversible fibrosis of the pancreas resulting from the cumulative injury sustained by the pancreas over time. It is an illness with variable presentations that can severely impact quality of life, while its long-term complications such as exocrine pancreatic insufficiency (EPI), diabetes mellitus, and risk of pancreatic cancer can become life threatening. The diagnosis of chronic pancreatitis can be challenging as despite the recent advancements in imaging technology, the radiographic findings do not become prominent until late stages of disease. Thus, the physicians' clinical acumen in obtaining thorough history taking focusing on risk factors, clinical symptoms, in addition to high-quality imaging, often guide to the accurate diagnosis of chronic pancreatitis. Endoscopy also plays a pivotal role in the diagnosis and management of chronic pancreatitis. Endoscopic ultrasound (EUS) is believed to be the most sensitive modality for diagnosing chronic pancreatitis. Despite efforts, however, natural history studies have demonstrated that 61% of individuals with chronic pancreatitis will require at least one endoscopic intervention, while 31% will require a surgical procedure as part of their management strategy. Recent advancements in genomic studies have furthered our understanding of the genetic polymorphisms that are associated with the pathogenesis of chronic pancreatitis. Genetic testing offers the potential to reveal treatable pancreatitis-related disorders, and can inform decision making with regard to radical therapies for persistent or severe disease such as total pancreatectomy with islet autotransplantation (TPIAT). The management of patients suffering from chronic pancreatitis often requires a multi-disciplinary approach, addressing pertinent symptoms as well as the sequelae of chronic inflammation and fibrosis. Abdominal pain is the prevailing symptom and most common complication of chronic pancreatitis, and impairs quality of life. Although heavily dependent on a wide range of analgesia, endoscopic treatment such as endoscopic retrograde cholangiopancreatography (ERCP) and surgical intervention can offer long-lasting relief of symptoms. For EPI, treatment with pancreatic enzyme supplements offers marginal-to-moderate relief. The most feared complication of chronic pancreatitis-the development of pancreatic cancer-has no known prevention measure to date.

Systematic review and meta-analysis: Is there any role for antioxidant therapy for pain in chronic pancreatitis

Chronic pancreatitis (CP) is an irreversible disease with increased oxidative stress. The therapeutic role of antioxidants for pain reduction in CP is debatable. A systematic review of articles in PubMed and Embase until February 2020 was performed. Only randomized controlled trials conducted on humans to evaluate the therapeutic effects of antioxidants for pain in CP were included. Studies of other design, nonhuman studies, and those that did not objectively assess pain were excluded. Twelve articles and four articles were eligible for qualitative and quantitative analysis, respectively. The four included studies had a total of 352 participants. Pain reduction as measured by a visual analog scale was not significantly different in the antioxidant group compared to placebo (standardized mean difference = -0.14 [95% confidence interval [CI] = -0.44 to 0.17]; P = 0.38). Number of pain-free participants was also similar (odds ratio [OR] = 1.59 [0.97-2.59]; P = 0.06). There was no difference in outcome when comparing different etiologies of CP or age group. The reduction in the number of analgesics used did not differ between both groups. Antioxidants were not associated with increased adverse events (OR = 2.59 [CI = 0.77-8.69]; P = 0.12). A qualitative analysis on the effect on quality of life did not suggest any significant improvement with antioxidants. There was no significant pain reduction or change in quality of life in CP patients with use of antioxidants. This makes their routine use in the management of CP questionable. However, further studies may identify a subgroup where they are more useful.

Progress in pharmacotherapy for alleviating pain of chronic pancreatitis

Pain is the main clinical symptom of chronic pancreatitis (CP), as well as the most common cause of patients' recurrent hospitalizations. The management regimen for CP pain needs to be formulated according to the patient's conditions. Lifestyle changes and drug treatment can usually be used as first-line therapy. Conventional analgesics, pancreatic enzymes, and antioxidants are commonly used in treating pain of CP. In recent years, the application of conventional analgesics has been further standardized. Besides, there have been more clinical studies on the treatment of CP pain with pancreatic enzymes or antioxidants. Traditional Chinese medicine has played an increasingly important role in the treatment of CP pain. New drugs such as camostat mesylate are expected to be used in CP pain, though more high-quality studies are still needed to confirm their safety and effectiveness.

Effect of traditional Chinese medicine formula GeGen decoction on primary dysmenorrhea: A randomized controlled trial study

ETHNOPHARMACOLOGICAL RELEVANCE

GeGen Decoction, a well-known Chinese herbal formula, is widely used in China and other Asian countries to treat gynecological diseases, including primary dysmenorrhea. Pharmacological studies have confirmed that GeGen Decoction is able to inhibit spasmodic contractions of the uterus in vivo and in vitro.

AIM OF THE STUDY

The objective of this study is to examine the efficacy and safety of GeGen Decoction on primary dysmenorrheic patients.

METHODS

This was a randomized, double-blinded, placebo-controlled trial. GeGen Decoction or placebo was administered a week before the expected start of each cycle for three consecutive menstrual periods. Between-group differences in pain intensity were detected by visual analogue scale (VAS). In addition, serum levels of arginine vasopressin (AVP) and estrogen (E) were examined by enzyme-linked immunosorbent assay. Metabolomic analysis was further used to evaluate the influence of GeGen Decoction on the metabolomics of primary dysmenorrheic patients.

RESULTS

A total of 71 primary dysmenorrheic women were recruited and 30 participants met the criteria were randomized into GeGen Decoction or placebo group. After three consecutive menstrual cycles' treatments, the VAS score of the GeGen Decoction group was significantly lower than that of the placebo group. Both serum levels of AVP and E decreased after GeGen Decoction administration, while the placebo seemed to have little effect on either of the index. Moreover, after GeGen Decoction treatment, seven important metabolites were identified by metabolomic analysis compared to the placebo group. No abnormalities in blood biochemical and routine physical examination pre and post GeGen Decoction intervention were observed.

CONCLUSIONS

GeGen Decoction can remarkably relieve the severity of menstrual pain without obvious adverse effects. Its therapeutic effect on primary dysmenorrhea might be related to the regulation of pituitary hypothalamic ovarian hormones, and interfering with the metabolic change.

Metabolic Consequences of Supplemented Methionine in a Clinical Context

The central position of methionine (Met) in protein metabolism indicates the importance of this essential amino acid for growth and maintenance of lean body mass. Therefore, Met might be a tempting candidate for supplementation. However, because Met is also the precursor of homocysteine (Hcy), a deficient intake of B vitamins or excessive intake of Met may result in hyperhomocysteinemia (HHcy), which is a risk factor for cardiovascular disease. This review discusses the evidence generated in preclinical and clinical studies on the importance and potentially harmful effects of Met supplementation and elaborates on potential clinical applications of supplemental Met with reference to clinical studies performed over the past 20 y. Recently acquired knowledge about the NOAEL (no observed adverse effect level) of 46.3 mg · kg-1 · d-1 and the LOAEL (lowest observed adverse effect level) of 91 mg · kg-1 · d-1 of supplemented Met will guide the design of future studies to further establish the role of Met as a potential (safe) candidate for nutritional supplementation in clinical applications.

Drainage procedure for pancreatolithiasis: re-examination of the pancreatic duct diameter standard

Purpose

Pancreatic duct decompression relieves pancreatic duct stone (PDS)-associated abdominal pain, though a consensus indication for the drainage procedure of the main pancreatic duct (MPD) is lacking. Moreover, major prognostic factors for postsurgical long-term pain relief and recurrence are largely unknown.

Methods

The clinical outcomes of 65 consecutive PDS patients undergoing surgery from 2008–2012 with 3+ years of follow-up were assessed.

Results

At postsurgical follow-up (median, 4.5 years; range, 3–7 years; procedure: Partington, n = 32; Frey, n = 27; pancreatoduodenectomy, n = 3; distal pancreatectomy, n = 3), the early complication and complete stone clearance rates were 29.2% and 97%, respectively. Long-term, complete and partial pain relief were 93.9%, 83.1%, and 10.8%, respectively. The risk of pancreatic fistula was higher in the <8 mm group than in the >8 mm group (P < 0.05), and 80% of the pancreatic fistula cases occurred in the <8 mm group. A shorter pain duration (P = 0.007), smaller MPD diameter (P = 0.04), and lower Izbicki pain score (P < 0.001) predicted long-term pain relief. Pain recurrence after initial remission occurred in 5 patients and was only related to pain duration (P = 0.02). Stone recurrence and pancreatic exocrine functional and endocrine functional deterioration occurred in 2, 5, and 11 patients, respectively.

Conclusion

Surgery provides excellent stone clearance, long-term pain relief, and acceptable postoperative morbidity. Using 8 mm as the criterion for drainage surgery can minimize the postoperative pancreatic fistula risk. Individualized and timely surgical treatment may improve the effect of surgery.

Antioxidants for Pancreatic Functions in Chronic Pancreatitis: A Double-blind Randomized Placebo-controlled Pilot Study

BACKGROUND

Antioxidants (AO) supplementation in chronic pancreatitis (CP) has been evaluated for pain. But it is not clear whether AO in CP have an effect on pancreatic functions and other clinical outcomes. We evaluated effect of AO on endocrine function in CP.

MATERIALS AND METHODS

Double-blind placebo (PL)-controlled randomized pilot study on 107 patients with CP assigned to receive daily combined AO or PL for 6 months. Primary outcome was: improvement in endocrine function (Homeostasis Model Assessment-Insulin Resistance). Secondary outcome measures were: improvement in C-peptide, Qualitative Insulin Sensitivity Check Index, exocrine pancreatic function (fecal elastase), surrogate markers of fibrosis (platelet-derived growth factor BB, transforming growth factor-β1, α-smooth muscle actin), quality of life (QOL), pain, nutritional status, markers of oxidative stress (OS), AO status, and inflammation.

RESULTS

There was an increase in levels of serum selenium (107.2±26.9 to 109.7±26.9 vs. 104.1±28.6 to 124.0±33.6 μg/L, P=0.022) and serum vitamin E [0.58 (range, 0.27-3.22) to 0.66 (range, 0.34-1.98) vs. 0.63 (range, 0.28-1.73) to 1.09 (range, 0.25-2.91) mg/dL, P=0.001] in the AO than the PL group. However, no significant differences were observed between groups in any of the primary or secondary outcome measures.

CONCLUSIONS

Supplementation with AO to patients with CP causes a sustained increase in blood levels of AO; however, it has no addition benefit over PL on endocrine and exocrine functions, markers of fibrosis, OS and inflammation, nutritional status, pain and QOL. Further larger studies with adequate sample size are required.

Pancreatic Stellate Cells Serve as a Brake Mechanism on Pancreatic Acinar Cell Calcium Signaling Modulated by Methionine Sulfoxide Reductase Expression

Although methionine sulfoxide reductase (Msr) is known to modulate the activity of multiple functional proteins, the roles of Msr in pancreatic stellate cell physiology have not been reported. In the present work we investigated expression and function of Msr in freshly isolated and cultured rat pancreatic stellate cells. Msr expression was determined by RT-PCR, Western blot and immunocytochemistry. Msr over-expression was achieved by transfection with adenovirus vectors. Pancreatic stellate cells were co-cultured with pancreatic acinar cells AR4-2J in monolayer culture. Pancreatic stellate and acinar cell function was monitored by Fura-2 calcium imaging. Rat pancreatic stellate cells were found to express MsrA, B1, B2, their expressions diminished in culture. Over-expressions of MsrA, B1 or B2 were found to enhance ATP-stimulated calcium increase but decreased reactive oxygen species generation and lipopolysaccharide-elicited IL-1 production. Pancreatic stellate cell-co-culture with AR4-2J blunted cholecystokinin- and acetylcholine-stimulated calcium increases in AR4-2J, depending on acinar/stellate cell ratio, this inhibition was reversed by MsrA, B1 over-expression in stellate cells or by Met supplementation in the co-culture medium. These data suggest that Msr play important roles in pancreatic stellate cell function and the stellate cells may serve as a brake mechanism on pancreatic acinar cell calcium signaling modulated by stellate cell Msr expression.

Earlier surgery improves outcomes from painful chronic pancreatitis

The timing of surgery for painful chronic pancreatitis (CP) may affect outcomes.Clinical course, Izbicki pain scores, and pancreatic function were retrospectively compared and analyzed between patients undergoing either early or late surgery (< 3 or ≥ 3 years from diagnosis) for painful CP in a single center from 2007 to 2012.The early surgery group (n = 98) more frequently than the late group (n = 199) had abdominal pain with jaundice (22.4% vs 9.5%, P = .002) and pancreatic mass +/- ductal dilatation (47% vs 27%, P < .001), but less frequently abdominal pain alone (73.5% vs 85.9%, P = .009), ductal dilatation alone (31% vs 71%, P < .001), parenchymal calcification (91.8% vs 100%, P < .001) or exocrine insufficiency (60% vs 72%, P = .034); there were no other significant differences. The early group had longer hospital stay (14.4 vs 12.2 days, P = .009), but no difference in complications. Significantly greater pain relief followed early surgery (complete 69% vs 47%, partial 22% vs 37%, none 8% vs 16%, P = .01) with lower rates of exocrine (60% vs 80%, P = .005) and endocrine insufficiency (36% vs 53%, P = .033).Our data indicate that early surgery results in higher rates of pain relief and pancreatic sufficiency than late surgery for chronic pancreatitis patients. Frey and Berne procedures showed better results than other surgical procedures.

Chronic pancreatitis

Chronic pancreatitis is defined as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress. Potential causes can include toxic factors (such as alcohol or smoking), metabolic abnormalities, idiopathic mechanisms, genetics, autoimmune responses and obstructive mechanisms. The pathophysiology of chronic pancreatitis is fairly complex and includes acinar cell injury, acinar stress responses, duct dysfunction, persistent or altered inflammation, and/or neuro-immune crosstalk, but these mechanisms are not completely understood. Chronic pancreatitis is characterized by ongoing inflammation of the pancreas that results in progressive loss of the endocrine and exocrine compartment owing to atrophy and/or replacement with fibrotic tissue. Functional consequences include recurrent or constant abdominal pain, diabetes mellitus (endocrine insufficiency) and maldigestion (exocrine insufficiency). Diagnosing early-stage chronic pancreatitis is challenging as changes are subtle, ill-defined and overlap those of other disorders. Later stages are characterized by variable fibrosis and calcification of the pancreatic parenchyma; dilatation, distortion and stricturing of the pancreatic ducts; pseudocysts; intrapancreatic bile duct stricturing; narrowing of the duodenum; and superior mesenteric, portal and/or splenic vein thrombosis. Treatment options comprise medical, radiological, endoscopic and surgical interventions, but evidence-based approaches are limited. This Primer highlights the major progress that has been made in understanding the pathophysiology, presentation, prevalence and management of chronic pancreatitis and its complications.

Guidelines for the understanding and management of pain in chronic pancreatitis

Abdominal pain is the foremost complication of chronic pancreatitis (CP). Pain can be related to recurrent or chronic inflammation, local complications or neurogenic mechanisms with corresponding changes in the nervous systems. Both pain intensity and the frequency of pain attacks have been shown to reduce quality of life in patients with CP. Assessment of pain follows the guidelines for other types of chronic pain, where the multidimensional nature of symptom presentation is taken into consideration. Quantitative sensory testing may be used to characterize pain, but is currently used in a research setting in advanced laboratories. For pain relief, current guidelines recommend a simple stepwise escalation of analgesic drugs with increasing potency until pain relief is obtained. Abstinence from alcohol and smoking should be strongly advised. Pancreatic enzyme therapy and antioxidants may be helpful as initial treatment. Endoscopic treatment can be used in patients with evidence of ductal obstruction and may be combined with extracorporeal shock wave lithothripsy. The best candidates are those with distal obstruction of the main pancreatic duct and in early stage of disease. Behavioral interventions should be part of the multidisciplinary approach to chronic pain management particularly when psychological impact is experienced. Surgery should be considered early and after a maximum of five endoscopic interventions. The type of surgery depends on morphological changes of the pancreas. Long-term effects are variable, but high success rates have been reported in open studies and when compared with endoscopic treatment. Finally, neurolytical interventions and neuromodulation can be considered in difficult patients.

Medical Management of Pain in Chronic Pancreatitis

The medical management of pain in chronic pancreatitis continues to pose significant challenges for clinicians caring for these patients. There are increasing data, suggesting that pain in chronic pancreatitis is largely due to peripheral and central sensitization that evolves, over time, as a result of nociceptive afferent associated with chronic inflammation and fibrosis of the pancreas. In many instances, patients rapidly progress to requiring opioid analgesics for the adequate treatment of pain despite the unequivocal risks associated with the long-term use of these drugs. Centrally acting drugs, such as gabapentinoids, appear to be effective means of treating pain due to their inhibition of neurotransmitters involved in central sensitization, but side effects limit their use. The present review explores the evidence for various non-pharmacologic and pharmacologic treatments for pain in chronic pancreatitis.

Long-term pain relief with optimized medical treatment including antioxidants and step-up interventional therapy in patients with chronic pancreatitis

BACKGROUND AND AIM

Abdominal pain is difficult to treat in patients with chronic pancreatitis (CP). Medical therapy including antioxidants has been shown to relieve pain of CP in the short-term. Our aim was to study the long-term results of optimized medical and interventional therapy for pain relief in patients with CP with a step-up approach.

METHODS

All consecutive patients with CP were included prospectively in the study. They were treated medically with a well-balanced diet, pancreatic enzymes, and antioxidants (9000 IU beta-carotene, 0.54 g vitamin C, 270 IU vitamin E, 600 µg organic selenium, and 2 g methionine). Endoscopic therapy and/or surgery were offered if medical therapy failed. Pain relief was the primary outcome measure.

RESULTS

A total of 313 patients (mean age 26.16 ± 12.17; 244 males) with CP were included; 288 (92%) patients had abdominal pain. The etiology of CP was idiopathic in 224 (71.6%) and alcohol in 82 (26.2%). At 1-year follow-up, significant pain relief was achieved in 84.7% of patients: 52.1% with medical therapy, 16.7% with endoscopic therapy, 7.6% with surgery, and 8.3% spontaneously. The mean pain score decreased from 6.36 ± 1.92 to 1.62 ± 2.10 (P < 0.001). Of the 288 patients, 261, 218, 112, and 51 patients were followed up for 3, 5, 10, and 15 years, respectively; 54.0%, 57.3%, 60.7%, and 68.8% of them became pain free at those follow-up periods.

CONCLUSION

Significant pain relief is achieved in the majority of patients with optimized medical and interventional treatment.

Ameliorating effect of antioxidants and pregabalin combination in pain recurrence after ductal clearance in chronic pancreatitis: Results of a randomized, double blind, placebo-controlled trial

BACKGROUND AND AIM

The aim of this study was to evaluate the effect of antioxidant-pregabalin combination on pain recurrence in patients with chronic calcific pancreatitis.

METHODS

In this randomized, double-blind, placebo-controlled trial, chronic calcific pancreatitis patients with pain recurrence following pancreatic ductal clearance of stones received either antioxidant-pregabalin combination or matching placebo for 2 months followed by open-label antioxidants for the next 4 months in both groups. Compliance, daily pain, and adverse events were recorded weekly and at the end of study by a coordinator blinded to treatment status. Primary outcome was pain improvement (visual analog scale and Izbicki score); secondary outcomes were as follows: complete pain resolution, painful days, and adverse events. Number needed-to-treat was calculated.

RESULTS

We randomized 42 and 45 patients (mean age 29.3 years) to treatment and placebo arms, respectively. Baseline characteristics, including pain scores, were similar for both groups. No patients received high-potency narcotic. At 2 months, a significant improvement in the treatment arm was observed in percent reduction of visual analog scale (-50 [-80.0; -32.1] vs -29.5 [-64.5; 0]; P = 0.01), Izbicki score (14.5 [0; 21.3] vs 30.0 [11.8; 41.3]; P = 0.001), complete pain resolution (20 [47.6%] vs 12 [26.7%]; P = 0.04), and number of painful days (10.0 [2.0; 16.0] vs 18.0 [7.0; 34.0]; P = 0.01). Needed-to-treat was 4.8. Pain reduction persisted at 6 months in the original treatment group (20.0 [15.0; 28.0] vs 36.0 [20.0; 50.0]; P = 0.006). A total of 33 patients in the treatment arm experienced mild to moderate self-limiting nausea/vomiting and drowsiness, respectively and did not require any change in study protocol.

CONCLUSION

Antioxidant-pregabalin combination results in significant relief in pain recurrence after ductal clearance in narcotic naïve patients with chronic calcific pancreatitis.

Clinical chronic pancreatitis

PURPOSE OF REVIEW

To summarize observations in clinical chronic pancreatitis in the past year.

RECENT FINDINGS

A predisposing genetic mutation was identified in 67% of cases of pediatric chronic pancreatitis. A novel susceptibility gene involving a hybrid allele is associated with idiopathic chronic pancreatitis. ABO blood type B and FUT2 nonsecretor status is associated with asymptomatic hyperlipasemia and chronic pancreatitis. Alcohol consumption impairs cystic fibrosis transmembrane conductance regulator (CFTR) activity leading to decreased bicarbonate secretion and patients with susceptible CFTR mutations can develop clinical pancreatitis. Computed tomography imaging findings in chronic pancreatitis correlate poorly with pain patterns. Endoscopic ultrasound features correlate poorly with fibrosis. Circulating epithelial cells are present in chronic pancreatitis patients but not healthy volunteers. Surgery is superior to endoscopic treatment in providing durable pain relief (>5 years). Repetitive pancreatic duct stent placements and chronic narcotic use are preoperative predictors of poor outcome after total pancreatectomy with islet cell auto transplantation.

SUMMARY

Novel genetic mutations for idiopathic chronic pancreatitis are being identified. Alcohol impairs CFTR activity and may explain a mechanism for pancreatitis. Current imaging modalities correlate poorly with clinical pain presentation and fibrosis in chronic pancreatitis. Novel imaging modalities are needed. As total pancreatectomy with islet cell auto transplantation grows, rigorous outcomes analysis is needed to drive patient selection.

The Analgesic Effect of the Mitochondria-Targeted Antioxidant SkQ1 in Pancreatic Inflammation

Background. Chronic pancreatitis is one of the main risk factors for pancreatic cancer. In acute and chronic pancreatitis, oxidative stress is thought to play a key role. In this respect, the recently described mitochondria-targeted antioxidant SkQ1 effectively scavenges reactive oxygen species at nanomolar concentrations. Therefore, we aimed to characterize the influence of SkQ1 on tissue injury and pain in acute and chronic pancreatitis. Methods. Both acute and chronic pancreatitis were induced in C57BL/6 mice by intraperitoneal cerulein injections and treatment with SkQ1 was carried out by peroral applications. Hyperalgesia was assessed by behavioral observation and measurement of abdominal mechanical sensitivity. Blood serum and pancreatic tissue were harvested for analysis of lipase and histology. Results. SkQ1 did not influence pain, serological, or histological parameters of tissue injury in acute pancreatitis. In chronic pancreatitis, a highly significant reduction of pain-related behavior (p < 0.0001) was evident, but histological grading revealed increased tissue injury in SkQ1-treated animals (p = 0.03). Conclusion. After SkQ1 treatment, tissue injury is not ameliorated in acute pancreatitis and increased in chronic pancreatitis. However, we show an analgesic effect in chronic pancreatitis. Further studies will need to elucidate the risks and benefits of mitochondria-targeted antioxidants as an analgesic.