Ghrelin and gastroparesis as early predictors of clinical outcomes in acute pancreatitis

Intra-pancreatic fat deposition across the pancreatitis spectrum and the influence of gut hormones

BACKGROUND AND AIMS

Acute pancreatitis (AP) and chronic pancreatitis (CP) often represent parts of the spectrum of disease. While growing evidence indicates that intra-pancreatic fat deposition (IPFD) plays an important role in the pathogenesis of pancreatitis, no study of living individuals has investigated IPFD in both AP and CP. Further, the associations between IPFD and gut hormones remain to be elucidated. The aims were to investigate the associations of IPFD with AP, CP, and health; and to study whether gut hormones affect these associations.

METHODS

Magnetic resonance imaging on the same 3.0 Tesla scanner was used to determine IPFD in 201 study participants. These participants were arranged into the health, AP, and CP groups. Gut hormones (ghrelin, glucagon-like peptide-1, gastric inhibitory peptide, peptide YY, and oxyntomodulin) were measured in blood, both after an 8-hour overnight fasting and after ingestion of a standardised mixed meal. A series of linear regression analyses was run, accounting for age, sex, ethnicity, body mass index, glycated haemoglobin, and triglycerides.

RESULTS

Both the AP group and CP group had significantly higher IPFD in comparison with the health group, consistently across all models (p for trend 0.027 in the most adjusted model). Ghrelin in the fasted state had a significant positive association with IPFD in the AP group (but not the CP or health group), consistently across all models (p = 0.019 in the most adjusted model). None of the studied gut hormones in the postprandial state was significantly associated with IPFD.

CONCLUSION

Fat deposition in the pancreas is similarly high in individuals with AP and those with CP. The gut-brain axis, and more specifically overexpression of ghrelin, may contribute to increased IPFD in individuals with AP.

Integrative effects of transcutaneous electrical acustimulation on abdominal pain, gastrointestinal motility, and inflammation in patients with early-stage acute pancreatitis

BACKGROUND/AIMS

Gastrointestinal (GI) dysmotility in acute pancreatitis (AP) aggravates inflammation and results in severe complications. This study aimed to explore effects and possible mechanisms of transcutaneous electrical acustimulation (TEA) on abdominal pain, GI dysmotility, and inflammation in AP patients.

METHODS

Forty-two AP patients were blindly randomized to receive TEA (n = 21) at acupoints PC6 and ST36 or Sham-TEA (n = 21) at sham points for 2 days. Symptom scores, gastric slow waves, autonomic functions (assessed by spectral analysis of heart rate variability), circulatory levels of motilin, ghrelin, and TNF-α were measured before and after the treatment. Sixteen healthy controls (HCs) were also included without treatment for the assessment of gastric slow waves and biochemistry.

KEY RESULTS

Compared with Sham-TEA, TEA decreased abdominal pain score (2.57 ± 1.78 vs. 1.33 ± 1.02, p < 0.05), bloating score (5.19 ± 1.21 vs. 0.76 ± 0.99, p < 0.001), the first defecation time (65.79 ± 19.51 h vs. 51.38 ± 17.19 h, p < 0.05); TEA, but not Sham-TEA, improved the percentage of normal gastric slow waves by 41.6% (p < 0.05), reduced AP severity score (5.52 ± 2.04 vs. 3.90 ± 1.90, p < 0.05) and serum TNF-α (7.59 ± 4.80 pg/ml vs. 4.68 ± 1.85 pg/ml, p < 0.05), and upregulated plasma ghrelin (0.85 ± 0.96 ng/ml vs. 2.00 ± 1.71 ng/ml, p = 0.001) but not motilin (33.08 ± 22.65 pg/ml vs. 24.12 ± 13.95 pg/ml, p > 0.05); TEA decreased sympathetic activity by 15.0% and increased vagal activity by 18.3% (both p < 0.05).

CONCLUSIONS & INFERENCES

TEA at PC6 and ST36 administrated at early stage of AP reduces abdominal pain, improves GI motility, and inhibits inflammatory cytokine, TNF-α, probably mediated via the autonomic and ghrelin mechanisms.

Relationship between Energy Balance and Circulating Levels of Hepcidin and Ferritin in the Fasted and Postprandial States

Markers of iron metabolism are altered in new-onset diabetes, but their relationship with metabolic signals involved in the maintenance of energy balance is poorly understood. The primary aim was to explore the associations between markers of iron metabolism (hepcidin and ferritin) and markers of energy balance (leptin, ghrelin, and the leptin/ghrelin ratio) in both the fasted and postprandial states. These associations were also studied in the sub-groups stratified by diabetes status. This was a cross-sectional study of individuals without disorders of iron metabolism who were investigated after an overnight fast and, in addition, some of these individuals underwent a mixed meal test to determine postprandial responses of metabolic signals. The associations between hepcidin, ferritin, and leptin, ghrelin, leptin/ghrelin ratio were studied using several multiple linear regression models. A total of 76 individuals in the fasted state and 34 individuals in the postprandial state were included. In the overall cohort, hepcidin was significantly inversely associated with leptin (in the most adjusted model, the β coefficient ± SE was -883.45 ± 400.94; p = 0.031) and the leptin/ghrelin ratio (in the most adjusted model, the β coefficient ± SE was -148.26 ± 61.20; p = 0.018) in the fasted state. The same associations were not statistically significant in the postprandial state. In individuals with new-onset prediabetes or diabetes (but not in those with normoglycaemia or longstanding prediabetes or diabetes), hepcidin was significantly inversely associated with leptin (in the most adjusted model, the β coefficient ± SE was -806.09 ± 395.44; p = 0.050) and the leptin/ghrelin ratio (in the most adjusted model, the β coefficient ± SE was -129.40 ± 59.14; p = 0.037). Leptin appears to be a mediator in the link between iron metabolism and new-onset diabetes mellitus. These findings add to the growing understanding of mechanisms underlying the derangements of glucose metabolism.

Motilin: a panoply of communications between the gut, brain, and pancreas

Introduction: Motilin was first alluded to nearly a century ago. But it remains a rather abstruse peptide, in the shadow of its younger but more lucid 'cousin' ghrelin.Areas covered: The review aimed to bring to the fore multifarious aspects of motilin research with a view to aiding prioritization of future studies on this gastrointestinal peptide.Expert opinion: Growing evidence indicates that rodents (mice, rats, guinea pigs) do not have functional motilin system and, hence, studies in these species are likely to have a minimal translational impact. Both the active peptide and motilin receptor were initially localized to the upper gastrointestinal tract only but more recently - also to the brain (in both humans and other mammals with functional motilin system). Motilin is now indisputably implicated in interdigestive contractile activity of the gastrointestinal tract (in particular, gastric phase III of the migrating motor complex). Beyond this role, evidence is building that there is a cross-talk between motilin system and the brain-pancreas axis, suggesting that motilin exerts not only contractile but also orexigenic and insulin secretagogue actions.

Cav 1.2 and Cav 2.2 expression is regulated by different endogenous ghrelin levels in pancreatic acinar cells during acute pancreatitis

Ghrelin influences pancreatic endocrine and exocrine functions, regulates intracellular calcium [Ca2+]i levels, and has an anti-inflammatory role in acute pancreatitis. This study investigated the role of endogenous ghrelin in the expression of Cav 1.2 (L-type of Ca2+ channel) and Cav 2.2 (N-type of Ca2+ channel) in acute pancreatitis. For this purpose, acute edematous pancreatitis (AEP) and acute necrotizing pancreatitis (ANP) rat models were established. Cav 1.2 and Cav 2.2 expression was assessed by immunohistochemistry in the pancreatic tissues of rats; ghrelin, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) serum levels were detected using ELISA. Next, in AR42J cells with either knock-out or overexpression of ghrelin, Cav 1.2 and Cav 2.2 expression was examined using western blot analysis, and intracellular calcium [Ca2+]i was detected with confocal microscopy. In this study, the ghrelin serum level was highest in the ANP group and was higher in the AEP group than the normal group. Expression of Cav 1.2 and Cav 2.2 in the ANP and AEP groups was higher than in the respective control groups. The serum IL-1β and TNF-α levels were significantly higher in the ANP group compared to the other groups. Cav 1.2 and Cav 2.2 expression and [Ca2+]i decreased in ghrelin knockdown AR42J cells but increased in ghrelin overexpressing cells. In conclusion, Cav 1.2 and Cav 2.2 expression increased in ANP. The [Ca2+]i level, which is mediated by Cav 1.2 and Cav 2.2 expression, is directly regulated by ghrelin in pancreatic acinar cells, and serum ghrelin levels may be involved in the severity of acute pancreatitis.

Effect of Intravenous Fluids and Analgesia on Dysmotility in Patients With Acute Pancreatitis: A Prospective Cohort Study

OBJECTIVES

Analgesia and intravenous fluid resuscitation are cornerstones of initial patient management in acute pancreatitis (AP). The aim was to investigate the effect of intravenous fluids and analgesia on gastrointestinal motility in the early course of AP.

METHODS

Gastrointestinal dysmotility was assessed using the Gastroparesis Cardinal Symptom Index (GCSI). One-way analysis of variance and analysis of covariance were conducted, adjusting for age, sex, body mass index, severity of AP, preexisting diabetes mellitus, and time from first symptom onset to hospital admission.

RESULTS

A total of 108 patients with AP were prospectively enrolled. Opioid analgesia, when compared with nonopioid analgesia, was significantly associated with increase in total GCSI score in both unadjusted and adjusted analyses. There was no significant difference between aggressive and nonaggressive fluid resuscitation in both unadjusted and adjusted analyses. A combination of opioids and any intravenous fluids was associated with a significantly increased total GCSI score compared with opioids and no intravenous fluids in both unadjusted and adjusted analyses. Duration of symptoms was the confounder that significantly affected 6 of 9 studied associations.

CONCLUSIONS

Intravenous fluids and analgesia significantly affect motility independent of severity and other covariates. Guidelines on prudent use of opioids and fluids in AP need to be developed, particularly taking into account duration of symptoms from onset to hospitalization.

Diabetes of the exocrine pancreas: American Diabetes Association-compliant lexicon

Multidisciplinary teams, including gastroenterologists, endocrinologists, surgeons, dietitians, primary care physicians, and other health professionals, are involved in management of individuals with diabetes of the exocrine pancreas (DEP). This necessitates introduction of a uniform terminology to ensure proper communication and reporting. Because DEP is a form of secondary diabetes mellitus, it makes sense to align the evolving DEP lexicon with nomenclature and diagnostic standards advocated by a world leading professional body in the field of diabetes such as the American Diabetes Association. This Editorial offers a historical excursus on the terms used and proposes a new concise nomenclature and diagnostic criteria. This new taxonomy of DEP, compliant with the American Diabetes Association standards of diagnosis and care for patients with diabetes mellitus, will ensure standardisation of reporting in future clinical studies on DEP and enable a dynamic incorporation of glucose dysregulation mechanisms related specifically to diseases of the exocrine pancreas as new evidence emerges.

Glucose Variability Measures as Predictors of Oral Feeding Intolerance in Acute Pancreatitis: A Prospective Pilot Study

BACKGROUND

Oral feeding intolerance (OFI) is a common complication in patients with acute pancreatitis (AP). Variations in blood glucose are associated with impaired gastrointestinal function but, to date, measures of glucose variability have not been investigated to predict OFI in patients with AP.

AIM

To investigate the usefulness of several glucose variability measures in predicting the occurrence of OFI early in the course of AP.

METHODS

In this prospective cohort study, six measures of glucose variability were calculated prior to the occurrence of OFI. Multivariate binary logistic regression analyses were conducted, and the diagnostic performance and accuracy of glucose variability measures were assessed.

RESULTS

Of the 95 prospectively enrolled patients, 21 (22%) developed OFI. After adjusting for confounders, admission blood glucose concentration and mean blood glucose concentration were significantly associated with OFI [odds ratio 1.49 (95% confidence interval 1.01-2.20) and odds ratio 1.67 (95% confidence interval 1.07-2.61), respectively]. Both admission blood glucose and mean blood glucose had an area under the curve of 0.83 and positive likelihood ratios of 6.45 and 10.19, respectively. Blood glucose concentration before refeeding, standard deviation of blood glucose concentration, coefficient of variation, and mean amplitude of glycemic excursions were not significantly associated with OFI.

CONCLUSION

In-hospital blood glucose concentrations are associated with subsequent development of OFI in patients with AP. In particular, admission blood glucose and mean blood glucose could be useful predictors of OFI in this setting.

New-Onset Diabetes After Acute and Critical Illness: A Systematic Review

Hyperglycemia is commonly observed during acute and critical illness. Recent studies have investigated the risk of developing diabetes after acute and critical illness, but the relationship between degree of in-hospital hyperglycemia and new-onset diabetes has not been investigated. This study examines the evidence for the relationship between in-hospital hyperglycemia and prevalence of new-onset diabetes after acute and critical illness. A literature search was performed of the MEDLINE, EMBASE, and Scopus databases for relevant studies published from January 1, 2000, through August 4, 2016. Patients with no history of diabetes before hospital discharge were included in the systematic review. In-hospital glucose concentration was classified as normoglycemia, mild hyperglycemia, or severe hyperglycemia for the meta-analysis. Twenty-three studies were included in the systematic review, and 18 of these (111,078 patients) met the eligibility criteria for the meta-analysis. The prevalence of new-onset diabetes was significantly related to in-hospital glucose concentration and was 4% (95% CI, 2%-7%), 12% (95% CI, 9%-15%), and 28% (95% CI, 18%-39%) for patients with normoglycemia, mild hyperglycemia, and severe hyperglycemia, respectively. The prevalence of new-onset diabetes was not influenced by disease setting, follow-up duration, or study design. In summary, this study found stepwise growth in the prevalence of new-onset diabetes with increasing in-hospital glucose concentration. Patients with severe hyperglycemia are at the highest risk, with 28% developing diabetes after hospital discharge.

The Role of Gut-brain Axis in Regulating Glucose Metabolism After Acute Pancreatitis

Objectives:

Diabetes has become an epidemic in developed and developing countries alike, with an increased demand for new efficacious treatments. A large body of pre-clinical evidence suggests that the gut–brain axis may be exploited as a potential therapeutic target for defective glucose homeostasis. This clinical study aimed to investigate a comprehensive panel of glucoregulatory peptides, released by both the gut and brain, in individuals after acute pancreatitis.

Methods:

Fasting levels of glucagon-like peptide-1 (GLP-1), glicentin, oxyntomodulin, peptide YY, ghrelin, cholecystokinin, vasoactive intestinal peptide (VIP), and secretin were studied. Modified Poisson and multivariable linear regression analyses were conducted. Pre-determined concentration ranges were used to categorize each peptide into quartiles.

Results:

A total of 83 individuals were included, of who 30 (36%) developed abnormal glucose metabolism (AGM) after acute pancreatitis. In individuals with AGM, the highest quartile of oxyntomodulin differed most significantly from the lowest quartile with a prevalence ratio (PR; 95% confidence interval) of 0.50 (0.21, 1.20; P=0.005); of glicentin with a PR of 0.26 (0.13, 0.54; P<0.001); and of VIP with a PR of 0.34 (0.13, 0.89; P=0.043). Peptide YY, GLP-1, cholecystokinin, ghrelin, and secretin were not significantly associated with AGM.

Conclusions:

Fasting circulating oxyntomodulin, glicentin, and VIP levels are significantly decreased in patients with defective glucose homeostasis after acute pancreatitis. Oxyntomodulin appears to be a promising therapeutic target for future clinical studies on diabetes associated with diseases of the exocrine pancreas.