Increased postprandial responses of GLP-1 and GIP in patients with chronic pancreatitis and steatorrhea following pancreatic enzyme substitution

Interactions between the Exocrine and the Endocrine Pancreas

The pancreas has two main functions: to produce and secrete digestive enzymes (exocrine function) and to produce hormones that regulate blood glucose and splanchnic secretion (endocrine function). The endocrine and exocrine portions of the pancreas are central regulators in digestion and metabolism, with continuous crosstalk between their deeply interconnected components, which plays a role in disease. Pancreatic neoplasms, inflammation, trauma, and surgery can lead to the development of type 3c diabetes when an insult simultaneously damages both acini and islets, leading to exocrine and endocrine dysfunction. In diabetes mellitus patients, pancreatic exocrine insufficiency is highly prevalent, yet little is known about the associations between diabetes mellitus and pancreatic exocrine function. This review aims to provide an overview of the physiology of the pancreas, summarize the pathophysiology and diagnostic work-up of pancreatic exocrine insufficiency, and explore the relationships between exocrine pancreatic insufficiency and diabetes mellitus.

Differential diagnosis of post pancreatitis diabetes mellitus based on pancreatic and gut hormone characteristics

PURPOSE

Distinguishing different types of diabetes is important in directing optimized treatment strategies and correlated epidemiological studies. Through detailed analysis of hormone responses to mixed meal tolerance test (MMTT), we aimed to find representing characteristics of post-acute pancreatitis diabetes mellitus (PPDM-A) and post-chronic pancreatitis diabetes mellitus (PPDM-C).

METHODS

Participants with PPDM-A, PPDM-C, type 1 diabetes, type 2 diabetes and normal controls underwent MMTT. Fasting and postprandial responses of serum glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, gastric inhibitory peptide (GIP), glucagon like peptide-1 (GLP-1) and peptide YY (PYY) were detected and compared among different groups. Focused analysis on calculated insulin sensitivity and secretion indices were performed to reason major causes of hyperglycemia in different conditions.

RESULTS

Participants with PPDM-A were characterized by increased C-peptide, insulin, glucagon and PP, while decreased ghrelin, GIP and PYY compared with controls. Patients with PPDM-C showed secretion insufficiency of C-peptide, insulin, ghrelin and PYY, higher postprandial responses of glucagon and PP than controls. In particular, both fasting and postprandial levels of ghrelin in PPDM-C were significantly lower than other diabetes groups. PYY responses in patients with PPDM-A and PPDM-C were markedly reduced. Besides, the insulin sensitivity of PPDM-A was decreased, and the insulin secretion for PPDM-C was decreased.

CONCLUSIONS

Along with the continuum from acute to chronic pancreatitis, the pathological mechanism of PPDM changes from insulin resistance to insulin deficiency. Insufficient PYY secretion is a promising diagnostic marker for distinguishing PPDM from type 1 and type 2 diabetes. Absent ghrelin secretion to MMTT may help identify PPDM-C.

Pancreatic enzyme replacement therapy in subjects with exocrine pancreatic insufficiency and diabetes mellitus: a real-life, case-control study

BACKGROUND

Exocrine pancreatic insufficiency (EPI) can be associated with all types of diabetes. Pancreatic enzyme replacement therapy (PERT) has short and long-term benefits in subjects with EPI, but its effects on diabetes control are uncertain. We aimed to study the effects of PERT initiation on glycemic control in subjects with diabetes and EPI from any cause.

METHODS

In this retrospective study, we compared subjects with EPI and diabetes who were prescribed PERT with subjects with diabetes who had a fecal elastase-1 concentration dosage, but did not receive PERT. The primary outcome was the effect of PERT on hypoglycemia frequency and severity. The secondary outcomes were the effects of PERT on gastro-intestinal disorders, HbA1c and body mass index (BMI).

RESULTS

48 subjects were included in each group. Overall, PERT did not have any significant effect on hypoglycemia frequency or severity, but hypoglycemia frequency tended to decrease in subjects with chronic pancreatitis. While 19% of subjects experienced mild hyperglycemia after PERT initiation, we did not report any keto-acidosis or any other severe adverse event. Gastro-intestinal disorders improved in 80% of subjects treated with PERT, versus in 20% of control subjects (p = 0.02). Gastro-intestinal disorders improved in 87% of subjects with recommended dosage of PERT, versus in 50% of subjects with underdosage (NS). HbA1c and BMI evolution did not differ between the groups.

CONCLUSIONS

PERT initiation is safe in subjects with diabetes and EPI. It does not globally decrease hypoglycemia severity of frequency, but is associated with a decrease in gastro-intestinal disorders. Trial registration Retrospectively registered. The database was registered with the Commission Nationale Informatique et Libertés (CNIL), registration number: 2203351v0. The study was approved by the local ethics committee CLEP, registration number: AAA-2023-09047.

Post-acute pancreatitis diabetes: A complication waiting for more recognition and understanding

Post-acute pancreatitis diabetes (PAPD) is the second most common type of diabetes below type 2 diabetes mellitus. Due to the boom in research on this entity carried out during the last decade, its recognition has increased. However, much of the medical community still does not recognize it as a medium and long-term complication of acute pancreatitis (AP). Recent prospective cohort studies show that its incidence is about 23% globally and 34.5% in patients with severe AP. With the overall increase in the incidence of AP this complication will be certainly seen more frequently. Due to its high morbidity, mortality and difficult control, early detection and treatment are essential. However, its risk factors and pathophysiological mechanisms are not clearly defined. Its diagnosis should be made excluding pre-existing diabetes and applying the criteria of the American Diabetes Association after 90 d of resolution of one or more AP episodes. This review will show the evidence published so far on the incidence and prevalence, risk factors, possible pathophysiological mechanisms, clinical outcomes, clinical characteristics and preventive and corrective management of PAPD. Some important gaps needing to be clarified in forthcoming studies will also be discussed.

Diabetes of the Exocrine Pancreas: Implications for Pharmacological Management

Post-pancreatitis diabetes mellitus, pancreatic cancer-related diabetes, and cystic fibrosis-related diabetes are often underappreciated. As a result, a substantial proportion of people with these sub-types of diabetes receive antidiabetic medications that may be suboptimal, if not harmful, in the context of their underlying disease of the exocrine pancreas. The present article delineates both classical (biguanides, insulin, sulfonylureas, α-glucosidase inhibitors, thiazolidinediones, and meglitinides) and newer (glucagon-like peptide-1 receptor agonists, amylin analogs, dipeptidyl peptidase-4 inhibitors, sodium-glucose co-transporter-2 inhibitors, D2 receptor agonists, bile acid sequestrants, and dual glucagon-like peptide-1 receptor and glucose-dependent insulinotropic polypeptide receptor co-agonists) therapies and provides recommendations for managing people with diabetes of the exocrine pancreas based on the most up-to-date clinical evidence. Also, several emerging directions (lipid-enriched pathways, Y4 receptor agonism, glucagon-like peptide-1 and glucagon receptor co-agonism) are presented with a view to informing the process of new drug discovery and development.

Pancreatic exocrine insufficiency in diabetes mellitus

Diabetes is disease of both the endo- and exocrine parts of the pancreas. Pancreatic exocrine insufficiency (PEI) can occur in every 2–3 patients with diabetes and affect not only the quality, but also life expectancy. At the same time, the diagnosis and treatment of PEI is not getting enough attention. The endocrinologist, as the main specialist leading patients with diabetes, can diagnose and treat patients with pancreatic exocrine insufficiency and diabetes using adequate doses of pancreatic enzyme replacement therapy (PERT).

Pancreatic exocrine insufficiency in diabetes mellitus

Diabetes is disease of both the endo- and exocrine parts of the pancreas. Pancreatic exocrine insufficiency (PEI) can occur in every 2–3 patients with diabetes and affect not only the quality, but also life expectancy. At the same time, the diagnosis and treatment of PEI is not getting enough attention. The endocrinologist, as the main specialist leading patients with diabetes, can diagnose and treat patients with pancreatic exocrine insufficiency and diabetes using adequate doses of pancreatic enzyme replacement therapy (PERT).

Effects of GLP-1 and GIP on Islet Function in Glucose-Intolerant, Pancreatic-Insufficient Cystic Fibrosis

Impaired insulin and incretin secretion underlie abnormal glucose tolerance (AGT) in pancreatic insufficient cystic fibrosis (PI-CF). Whether the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) can enhance pancreatic islet function in cystic fibrosis (CF) is not known. We studied 32 adults with PI-CF and AGT randomized to receive either GLP-1 (n = 16) or GIP (n = 16) during glucose-potentiated arginine (GPA) testing of islet function on two occasions, with either incretin or placebo infused, in a randomized, double-blind, cross-over fashion. Another four adults with PI-CF and normal glucose tolerance (NGT) and four matched control participants without CF underwent similar assessment with GIP. In PI-CF with AGT, GLP-1 substantially augmented second-phase insulin secretion but without effect on the acute insulin response to GPA or the proinsulin secretory ratio (PISR), while GIP infusion did not enhance second-phase or GPA-induced insulin secretion but increased the PISR. GIP also did not enhance second-phase insulin in PI-CF with NGT but did so markedly in control participants without CF controls. These data indicate that GLP-1, but not GIP, augments glucose-dependent insulin secretion in PI-CF, supporting the likelihood that GLP-1 agonists could have therapeutic benefit in this population. Understanding loss of GIP's insulinotropic action in PI-CF may lead to novel insights into diabetes pathogenesis.

The spectrum of diabetes in acute and chronic pancreatitis

PURPOSE OF REVIEW

To discuss the spectrum of diabetes related to acute and chronic pancreatitis (which are types of pancreatogenic diabetes) and its overlapping features with type 1 and type 2 diabetes.

RECENT FINDINGS

Patients with diabetes related to acute and chronic pancreatitis present clinically within a spectrum of overlapping features with other forms of diabetes. In this spectrum, glucose metabolism alterations range from increased insulin resistance following acute pancreatitis (resembling type 2 diabetes) towards a permanent loss of beta-cell function and impaired insulin secretion in end-stage chronic pancreatitis. Overlapping features with type 1 diabetes (beta cell autoantibodies) and type 2 diabetes (obesity, dyslipidemia, and hereditary/genetic factors) contribute to the heterogeneity of this spectrum.

SUMMARY

Pancreatogenic diabetes secondary to acute or chronic pancreatitis is a heterogeneous entity with a variable clinical presentation, including many cases that are misdiagnosed and treated as type 2 diabetes. This is problematic as pancreatogenic diabetes is associated with a poor prognosis and entails special considerations for management. Recent discoveries showing overlapping features with type 1 and type 2 diabetes along with an improved understanding of its pathophysiology are expected to improve the diagnosis and treatment of these and other forms of pancreatogenic diabetes.

GLP-1 Agonist to Treat Obesity and Prevent Cardiovascular Disease: What Have We Achieved so Far?

PURPOSE OF REVIEW

To discuss evidence supporting the use of glucagon-like peptide 1 receptor agonists (GLP-1RA) to treat obesity and their role as a cardioprotective drug. Obesity is not just a hypertrophy of the adipose tissue because it may become dysfunctional and inflamed resulting in increased insulin resistance. Being overweight is associated with increased incidence of cardiovascular events and weight loss achieved through lifestyle changes lowers risk factors, but has no clear effect on cardiovascular outcomes. In contrast, treating obesity with GLP-1RA decreases cardiovascular risk and the possible mechanisms of cardioprotection achieved by this class of drugs are discussed. GLP-1RA were initially developed to treat type 2 diabetes patients, in whom the effects upon glycemia and, moreover, weight loss, especially with long-acting GLP-1RA, were evident. However, cardiovascular safety trials in type 2 diabetes patients, the majority presenting cardiovascular disease and excess weight, showed that GLP-1 receptor agonists were indeed capable of decreasing cardiovascular risk.

RECENT FINDINGS

Type 2 diabetes treatment with GLP-1RA liraglutide and semaglutide paved way to a ground-breaking therapy specific for obesity, as shown with the SCALE 3 mg/day liraglutide program and the STEP 2.4 mg/week semaglutide program. A novel molecule with superior performance is tirzepatide, a GLP-1 and GIP (Gastric Inhibitory Peptide) receptor agonist and recent results from the SURPASS and SURMOUNT programs are briefly described. Liraglutide was approved without a CVOT (Cardiovascular Outcome Trial) because authorities accepted the results from the LEADER study, designed for superiority. The SELECT study with semaglutide will report results only in 2023 and tirzepatide is being tested in patients with diabetes in the SURPASS-CVOT. Clinical studies highlight that GLP-1RA to treat obesity, alongside their concomitant cardioprotective effects, have become a hallmark in clinical science.

Pancreatic and gut hormone responses to mixed meal test in post-chronic pancreatitis diabetes mellitus

OBJECTIVE

. - More than one-third of chronic pancreatitis patients will eventually develop diabetes, recently classified as post-chronic pancreatitis diabetes mellitus (PPDM-C). This study was aimed to investigate the pancreatic and gut hormone responses to a mixed meal test in PPDM-C patients, compared with non-diabetic chronic pancreatitis (CP), and type 2 diabetes patients or healthy controls.

DESIGN AND METHODS

.- Sixteen patients with PPDM-C, 12 with non-diabetic CP as well as 10 with type 2 diabetes and healthy controls were recruited. All participants underwent mixed meal tests, and blood samples were collected for measurements of blood glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, peptide YY, glucagon like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP). Indices of insulin sensitivity and secretion were calculated. Repeated measures analysis of variance was performed.

RESULTS

. - Participants with PPDM-C exhibited decreases in both fasting and postprandial responses of C-peptide (P < 0.001), insulin (P < 0.001), ghrelin (P < 0.001) and PYY (P = 0.006) compared to participants with type 2 diabetes and healthy controls. Patients with CP showed blunted glucagon, PP and incretin reactions, while the responses were increased in patients with PPDM-C compared to controls. The level of insulin sensitivity was higher for PPDM-C than type 2 diabetes (P < 0.01), however the indices for early/late-phase and overall insulin secretion (P < 0.01) were lower.

CONCLUSIONS

.- Patients with PPDM-C are characterized by decreased C-peptide, insulin, ghrelin and PYY responses, and similar levels of glucagon, PP, GIP and GLP-1 compared to those with type 2 diabetes. The above findings, when confirmed in a larger population, may prove helpful to establish the diagnosis of PPDM-C, and should promote study on underlying pathophysiological mechanisms.

Pancreatogenic Diabetes, 2 Onset Forms and Lack of Metabolic Syndrome Components Differentiate It From Type 2 Diabetes

OBJECTIVES

We compared pancreatogenic (DM3c) and type 2 diabetes mellitus.

METHODS

We compared age-, sex-, and diabetes mellitus duration-matched DM3c cases (n = 142) and type 2 diabetes mellitus (n = 142). Pancreatogenic diabetes was considered when it appeared after the diagnosis of pancreatitis or after pancreatic surgery.

RESULTS

Pancreatogenic diabetes presented lower body mass index (BMI) [odds ratio (OR), 1.2; 95% confidence interval (CI), 1.13-1.28; P < 0.001], worse glycemic control (OR, 1.196; 95% CI, 1.058-1.35; P = 0.004), required insulin more frequently (OR, 4.21; 95% CI, 2.57-6.93; P = 0.0001), had more hypoglycemic episodes (OR, 3.65; 95% CI, 1.64-8.16; P = 0.001) but lower frequency of dyslipidemia (OR, 0.42; 95% CI, 0.26-0.68; P = 0.001) and arterial hypertension (OR, 0.52; 95% CI, 0.32-0.86; P = 0.01). Pancreatogenic diabetes cases on pancreatic enzyme replacement therapy had lower glycosylated hemoglobin (8.52% vs 9.44%; P = 0.026), serum carotenes (79.1 vs 116.1; P = 0.03), and BMI (23.4 vs 26.1; P = 0.0005) than those not on pancreatic enzyme replacement therapy. Pancreatogenic diabetes onset occurred earlier in necrotizing pancreatitis and after pancreatic surgery.

CONCLUSIONS

Pancreatogenic diabetes presents with low BMI and lacks metabolic syndrome components. The type of pancreatic disease or surgery defines its onset time.

Complications of chronic pancreatitis in children

PURPOSE OF REVIEW

In children, chronic pancreatitis is infrequent but may be associated with serious complications, including severe pain that limits activities, exocrine and endocrine pancreatic insufficiency and malnutrition. Investigation into pediatric chronic pancreatitis has transitioned from single center reports to multicenter, protocol-driven studies. As a result, we now have information on much larger numbers of children with chronic pancreatitis, allowing a more reliable understanding of the complications of chronic pancreatitis.

RECENT FINDINGS

A high percentage of children with chronic pancreatitis use opioids frequently to control pain. About a quarter of children with chronic pancreatitis have exocrine pancreatic insufficiency, and about 6% have pancreatogenic diabetes. Mild malnutrition and low bone density are both common in children with chronic pancreatitis.

SUMMARY

Large multicenter and single-center observational studies have allowed us to more accurately assess complications of chronic pancreatitis in children. These studies demonstrate the need for examination of therapies for these complications in children.

Incretins in fibrocalculous pancreatic diabetes: A unique subtype of pancreatogenic diabetes

BACKGROUND

Studies evaluating endocrine and exocrine functions in fibrocalculous pancreatic diabetes (FCPD) are scarce.

METHODS

Insulin, C-peptide, glucagon, incretin hormones (glucagon-like peptide 1 [GLP-1] and gastric inhibitory peptide [GIP]), and dipeptidyl peptidase IV (DPP-IV) were estimated in patients with FCPD (n = 20), type 2 diabetes mellitus (T2DM) (n = 20), and controls (n = 20) in fasting and 60 minutes after 75 g glucose.

RESULTS

Fasting and post-glucose C-peptide and insulin in FCPD were lower than that of T2DM and controls. Plasma glucagon decreased after glucose load in controls (3.72, 2.29), but increased in T2DM (4.01, 5.73), and remained unchanged in FCPD (3.44, 3.44). Active GLP-1 (pmol/L) after glucose load increased in FCPD (6.14 to 9.72, P = <.001), in T2DM (2.87 to 4.62, P < .001), and in controls (3.91 to 6.13, P < .001). Median active GLP-1 in FCPD, both in fasting and post-glucose state (6.14, 9.72), was twice that of T2DM (2.87, 4.62) and 1.5 times that of controls (3.91, 6.13) (P < .001 for all). Post-glucose GIP (pmol/L) increased in all: FCPD (15.83 to 94.14), T2DM (21.85 to 88.29), and control (13.00 to 74.65) (P < .001 for all). GIP was not different between groups. DPP-IV concentration (ng/mL) increased in controls (1578.54, 3012.00) and FCPD (1609.95, 1995.42), but not in T2DM (1204.50, 1939.50) (P = .131). DPP-IV between the three groups was not different. Fecal elastase was low in FCPD compared with T2DM controls.

CONCLUSIONS

In FCPD, basal C-peptide and glucagon are low, and glucagon does not increase after glucose load. GLP-1, but not GIP, in FCPD increases 1.5 to 2 times as compared with T2DM and controls (fasting and post glucose) without differences in DPP-IV.

Pancreatic atrophy and exocrine insufficiency associate with the presence of diabetes in chronic pancreatitis patients, but additional mediators are operative

OBJECTIVES

Diabetes mellitus is a frequent complication of chronic pancreatitis (CP) and has traditionally been considered to develop as a consequence of pancreatic islet cell loss. However, additional mechanisms may be operative including accumulation of pancreatic fat and fibrosis. We used advanced magnetic resonance imaging (MRI) to study pancreatic morphology and exocrine function in a reference population and in CP patients with and without diabetes.

METHODS

This was a cross-sectional mono centre study. All subjects underwent advanced MRI including assessment of pancreatic ductal parameters (Cambridge classification and main pancreatic duct diameter), parenchymal parameters (DIXON technique and diffusion weighted imaging as proxies for pancreatic fat content and fibrosis, as well as pancreatic volume segmentation). Pancreatic exocrine function was determined as duodenal secretion following secretin stimulation and by the faecal elastase test.

RESULTS

The study included 76 patients with definite CP of whom 23 (30.1%) had diabetes and 23 sex- and age matched healthy volunteers. Compared to their non-diabetic counterparts, diabetic patients were characterised by a low pancreatic volume (20 vs. 36 ml; p = .02) and impaired pancreatic exocrine function (faecal elastase 19 vs. 48 µg/g; p = .008), while no difference between patients with and without diabetes were seen in relation to MRI derived proxies for fibrosis and pancreatic fat accumulation and pancreatic duct parameters. A large proportion of non-diabetic patients (49%) had similar morphological and functional characteristics as patients with diabetes.

CONCLUSION

Pancreatic atrophy and exocrine insufficiency are present in most CP patients with diabetes, but additional mediators seem to be operative in post pancreatitis diabetes mellitus.

Medical Management of Chronic Pancreatitis in Children: A Position Paper by the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Pancreas Committee

ABSTRACT

This position paper summarizes the current understanding of the medical management of chronic pancreatitis (CP) in children in light of the existing medical literature, incorporating recent advances in understanding of nutrition, pain, lifestyle considerations, and sequelae of CP. This article complements and is intended to integrate with parallel position papers on endoscopic and surgical aspects of CP in children. Concepts and controversies related to pancreatic enzyme replacement therapy (PERT), the use of antioxidants and other CP medical therapies are also reviewed. Highlights include inclusion of tools for medical decision-making for PERT, CP-related diabetes, and multimodal pain management (including an analgesia ladder). Gaps in our understanding of CP in children and avenues for further investigations are also reviewed.

Risk factors for development of endocrine insufficiency in chronic pancreatitis

Endocrine insufficiency is a common and frequent complication of chronic pancreatitis. Identifying the role of pancreatic damage in the development of diabetes is important for early identification and appropriate management.

METHODS

All consecutive CP patients between January 2019 and May 2020 were retrospectively studied. Relevant statistical tests were performed. A two sided p value < 0.05 was considered statistically significant.

RESULTS

Total 587 chronic pancreatitis patients were included of which 118 (20.1%) patients developed diabetes with duration of 12 (IQR 4-48) months. Older age (OR 1.079; 95% CI 1.045-1.113; p < 0.001), presence of pancreatic parenchymal (OR 2.284; 95% CI 1.036-5.038; p = 0.041) and ductal (OR 2.351; 95% CI 1.062-5.207; p = 0.035) calcifications, exocrine insufficiency (OR 6.287; 95% CI 2.258-17.504; p < 0.001), and pancreatic duct stricture (OR 3.358; 95% CI 1.138-9.912; p = 0.028) were independently associated with development of diabetes mellitus in chronic pancreatitis patients. On cox-regression analysis, smoking (HR 2.370; 95% CI 1.290-4.354; p = 0.005) and pancreatic ductal calcification (HR 2.033; 95% CI 1.286-3.212; p = 0.002) were independently associated with earlier onset of diabetes mellitus in patients with chronic pancreatitis.

CONCLUSION

Pancreatic calcification, pancreatic duct stricture and pancreatic exocrine insufficiency are associated with development of diabetes mellitus in chronic pancreatitis indicating disease progression. Smoking is the modifiable risk factors associated with early onset of diabetes mellitus in CP patients.

Pilot study examining the impact of a specialist multidisciplinary team clinic for patients with chronic pancreatitis

OBJECTIVE

-To assess the efficacy of a pilot Chronic Pancreatitis (CP) Multidisciplinary (MDT) clinic.

METHODS

- 60 patients referred to a pilot MDT CP clinic were analysed. Anthropometric data, nutrition status, malabsorption evidence, glycaemic control, opiate use, bone mineral density (BMD) assessment and quality of life (QoL) were examined.

RESULTS

-The average age was 51.27 (±12.75). The commonest aetiology was alcohol (55%). Ninety one point five percent had evidence of ongoing pancreatic exocrine insufficiency, with 88.1% requiring initiation or up-titration of pancreatic enzyme replacement (PERT). Up to half of the patients exhibited micronutrient deficiency. Twenty eight percent were diagnosed with type IIIc diabetes. There was an average daily reduction of 6 mg of morphine usage per patient with a concurrent decline in median pain scores from 83.3 to 63.3, which was non-significant. The median QoL score was 33.3 compared to a score of 75 from the reference population. QoL scores increased from 31.0 to 37.3 at follow up appointments. Seventy two point five percent of patients had undiagnosed low BMD.

CONCLUSION

The data suggest that CP patients have significant nutritional deficiencies as well as undiagnosed diabetes, poor pain and glycaemic control which negatively impacts QoL. Assessment in a multi-disciplinary clinic ensures appropriate management.

Pathological Mechanisms in Diabetes of the Exocrine Pancreas: What's Known and What's to Know

The clinical significance of diabetes arising in the setting of pancreatic disease (also known as diabetes of the exocrine pancreas, DEP) has drawn more attention in recent years. However, significant improvements still need to be made in the recognition, diagnosis and treatment of the disorder, and in the knowledge of the pathological mechanisms. The clinical course of DEP is different from type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). DEP develops in patients with previous existing exocrine pancreatic disorders which damage both exocrine and endocrine parts of pancreas, and lead to pancreas exocrine insufficiency (PEI) and malnutrition. Therefore, damage in various exocrine and endocrine cell types participating in glucose metabolism regulation likely contribute to the development of DEP. Due to the limited amount of clinical and experimental studies, the pathological mechanism of DEP is poorly defined. In fact, it still not entirely clear whether DEP represents a distinct pathologic entity or is a form of T2DM arising when β cell failure is accelerated by pancreatic disease. In this review, we include findings from related studies in T1DM and T2DM to highlight potential pathological mechanisms involved in initiation and progression of DEP, and to provide directions for future research studies.

A tale of two pancreases: exocrine pathology and endocrine dysfunction

The islets of Langerhans are well embedded within the exocrine pancreas (the latter comprised of ducts and acini), but the nature of interactions between these pancreatic compartments and their role in determining normal islet function and survival are poorly understood. However, these interactions appear to be critical, as when pancreatic exocrine disease occurs, islet function and insulin secretion frequently decline to the point that diabetes ensues, termed pancreatogenic diabetes. The most common forms of pancreatogenic diabetes involve sustained exocrine disease leading to ductal obstruction, acinar inflammation, and fibro-fatty replacement of the exocrine pancreas that predates the development of dysfunction of the endocrine pancreas, as seen in chronic pancreatitis-associated diabetes and cystic fibrosis-related diabetes and, more rarely, MODY type 8. Intriguingly, a form of tumour-induced diabetes has been described that is associated with pancreatic ductal adenocarcinoma. Here, we review the similarities and differences among these forms of pancreatogenic diabetes, with the goal of highlighting the importance of exocrine/ductal homeostasis for the maintenance of pancreatic islet function and survival and to highlight the need for a better understanding of the mechanisms underlying these diverse conditions. Graphical abstract.

Islet cell dysfunction in patients with chronic pancreatitis

Chronic pancreatitis (CP) is characterized by progressive inflammation and fibrosis of the pancreas that eventually leads to pancreatic exocrine and endocrine insufficiency. Diabetes in the background of CP is very difficult to manage due to high glycemic variability and concomitant malabsorption. Progressive beta cell loss leading to insulin deficiency is the cardinal mechanism underlying diabetes development in CP. Alpha cell dysfunction leading to deranged glucagon secretion has been described in different studies using a variety of stimuli in CP. However, the emerging evidence is varied probably because of dependence on the study procedure, the study population as well as on the stage of the disease. The mechanism behind islet cell dysfunction in CP is multifactorial. The intra-islet alpha and beta cell regulation of each other is often lost. Moreover, secretion of the incretin hormones such as glucagon like peptide-1 and glucose-dependent insulinotropic polypeptide is dysregulated. This significantly contributes to islet cell disturbances. Persistent and progressive inflammation with changes in the function of other cells such as islet delta cells and pancreatic polypeptide cells are also implicated in CP. In addition, the different surgical procedures performed in patients with CP and antihyperglycemic drugs used to treat diabetes associated with CP also affect islet cell function. Hence, different factors such as chronic inflammation, dysregulated incretin axis, surgical interventions and anti-diabetic drugs all affect islet cell function in patients with CP. Newer therapies targeting alpha cell function and beta cell regeneration would be useful in the management of pancreatic diabetes in the near future.

Exocrine Pancreatic Insufficiency in Type 1 and Type 2 Diabetes

PURPOSE OF REVIEW

Type 1 and type 2 diabetes are often accompanied by mostly mild forms of exocrine pancreatic insufficiency. Despite high prevalence, little is known about the clinical consequences of exocrine pancreatic insufficiency and its optimal (nutritional) treatment. Even less is known if and to what extent exocrine pancreas insufficiency also affects glycemic control in diabetes. This article aims for summarizing current clinical knowledge on screening, diagnosis, and treatment and gives an overview on the pathophysiology of exocrine pancreatic insufficiency in diabetes.

RECENT FINDINGS

Recent studies reveal novel insights into the close interaction of acinar, ductal, and endocrine cells and the gut-pancreas axis. Exocrine pancreatic insufficiency is a clinically relevant, frequent but poorly understood disorder in both type 1 and type 2 diabetes.

Risk Factors Associated With Progression Toward Endocrine Insufficiency in Chronic Pancreatitis

OBJECTIVE

Little data exist describing the change over time in islet function and glycemic control in patients with chronic pancreatitis (CP).

METHODS

In 325 CP patients who underwent 2 mixed meal tolerance tests and/or glycated hemoglobin (HbA1c) levels, we estimated the rate of change in metabolic measures per 6 months and assessed the association between potential risk factors for diabetes and rate of change using multivariate regression models.

RESULTS

Per 6-month time, HbA1c increased by 0.062% with a standard error of 0.029% (P = 0.037) and the ratio (area under the curve (AUC) C-peptide to AUC glucose from mixed meal tolerance testing) decreased by 0.0028 with a standard error of 0.0011 (P = 0.014). We observed more rapid decline in smokers (AUC C-peptide, P = 0.043) and patients with surgical drainage (AUC glucose, P = 0.001; ratio, P = 0.03) or with calcific pancreatitis (HbA1c, P = 0.003). In multivariate models, AUC C-peptide and ratio declined at a greater rate in smokers and HbA1c in those with pancreatic calcifications (both P < 0.05).

CONCLUSIONS

We observed a measurable decline in β-cell function and glycemic control in patients with CP. Patients with a history of tobacco smoking, surgical drainage, or pancreatic calcification may be at highest risk.

The prevalence and impact of low faecal elastase-1 in community-based patients with type 2 diabetes

AIMS

To determine the prevalence of low faecal elastase-1 (FE-1) (≤200 μg/g) in type 2 diabetes (T2DM), and to test the hypothesis that pancreatic enzyme replacement therapy (PERT) would reduce postprandial glycaemia after a high-fat, high-carbohydrate meal in T2DM subjects with low FE-1.

METHODS

Of 109 community-based patients who submitted stool samples, 10 had low FE-1 and 8 were recruited (6 male, 2 female, 67.8 ± 3.0 years). Participants were given a high-fat, high-carbohydrate meal (718 kcal) with either pancrelipase (50,000 units) or placebo in a randomised, double-blind, crossover fashion. The primary outcome was the difference in postprandial glycaemia following PERT vs placebo, as evaluated by the incremental area under the postprandial plasma glucose curve (iAUC). Secondary outcomes included differences in gastric half-emptying time (T50) measured using scintigraphy, and C-peptide iAUC.

RESULTS

The prevalence of low FE-1 in T2DM was 9.2% (95% CI 3.8-14.6%). There was no difference in postprandial glycaemia iAUC (P = 0.38), gastric emptying T50 (P = 0.69) or C-peptide iAUC (P = 0.25) after PERT compared to placebo.

CONCLUSIONS

Decreased FE-1 has a relatively low prevalence in community-based patients with T2DM, and PERT does not reduce postprandial glycaemia in these patients.

CLINICAL TRIAL REGISTRATION NUMBER

ACTRN12617000349347.

Pancreatic exocrine insufficiency in diabetes mellitus - prevalence and characteristics

BACKGROUND

The prevalence of pancreatic exocrine insufficiency (PEI) in diabetes mellitus (DM) varies widely between studies, which may be explained by methodological problems. We aimed to establish the prevalence of PEI in DM using the faecal elastase-1 (FE-1) assay as a screening test, and to further investigate these patients by the mixed ¹³C-triglyceride (¹³C-MTG) breath test.

METHODS

One hundred and thirty-three consecutive type 1 or type 2 DM patients without known exocrine pancreatic disorders were recruited. Demographic parameters, stool consistency, stool frequency, routine laboratory tests, and the presence of DM complications were registered. An FE-1 value <200 μg/g was used as the screening cut-off for PEI, and patients with FE-1 values below this level were referred for a ¹³C-MTG breath test.

RESULTS

One hundred and two patients returned faecal samples. The prevalence of PEI as measured by low FE-1 was 13%. Insulin usage, type 1 DM, and DM duration were associated with low FE-1. Stool habits were unaffected by low FE-1. Twelve out of 13 patients with low FE-1 performed the breath test, which was normal in all cases.

CONCLUSIONS

The prevalence of PEI defined by FE-1 was low in our mixed cohort of type 1 and 2 DM patients. Furthermore, there was a discrepancy between FE-1 and the breath test. Hence, the role of FE-1 in evaluating pancreatic exocrine function in DM should be evaluated in larger studies in order to clarify the association between low FE-1 and clinically relevant PEI.

Role of Fibre in Nutritional Management of Pancreatic Diseases

The role of fibre intake in the management of patients with pancreatic disease is still controversial. In acute pancreatitis, a prebiotic enriched diet is associated with low rates of pancreatic necrosis infection, hospital stay, systemic inflammatory response syndrome and multiorgan failure. This protective effect seems to be connected with the ability of fibre to stabilise the disturbed intestinal barrier homeostasis and to reduce the infection rate. On the other hand, in patients with exocrine pancreatic insufficiency, a high content fibre diet is associated with an increased wet fecal weight and fecal fat excretion because of the fibre inhibition of pancreatic enzymes. The mechanism by which dietary fibre reduces the pancreatic enzyme activity is still not clear. It seems likely that pancreatic enzymes are absorbed on the fibre surface or entrapped in pectin, a gel-like substance, and are likely inactivated by anti-nutrient compounds present in some foods. The aim of the present review is to highlight the current knowledge on the role of fibre in the nutritional management of patients with pancreatic disorders.

Structure and function of the exocrine pancreas in patients with type 1 diabetes

In the last 10 years, several studies have shown that the pancreas of patients with type 1 diabetes (T1D), and even of subjects at risk for T1D, was smaller than the pancreas from healthy subjects. This arose the question of the relationships between the endocrine and exocrine parts of the pancreas in T1D pathogenesis. Our review underlines that histological anomalies of the exocrine pancreas are common in patients with T1D: intralobular and interacinar fibrosis, acinar atrophy, fatty infiltration, leucocytic infiltration, and pancreatic arteriosclerosis are all frequent observations. Moreover, 25% to 75% of adult patients with T1D present with pancreatic exocrine dysfunction. Our review summarizes the putative causal factors for these structural and functional anomalies, including: 1/ alterations of insulin, glucagon, somatostatin and pancreatic polypeptide secretion, 2/ global pancreatic inflammation 3/ autoimmunity targeting the exocrine pancreas, 4/ vascular and neural abnormalities, and 5/ the putative involvement of pancreatic stellate cells. These observations have also given rise to new theories on T1D: the primary event of T1D pathogenesis could be non-specific, e.g bacterial or viral or chemical, resulting in global pancreatic inflammation, which in turn could cause beta-cell predominant destruction by the immune system. Finally, this review emphasizes that it is advisable to evaluate pancreatic exocrine function in patients with T1D presenting with gastro-intestinal complaints, as a clinical trial has shown that pancreatic enzymes replacement therapy can reduce the frequency of hypoglycemia and thus might improve quality of life in subjects with T1D and exocrine failure.

Glucagon-Like Peptide-1 Receptor Agonists and Strategies To Improve Their Efficiency

Type 2 diabetes mellitus (T2DM) is increasing in global prevalence and is associated with serious health problems (e.g., cardiovascular disease). Various treatment options are available for T2DM, including the incretin hormone glucagon-like peptide-1 (GLP-1). GLP-1 is a therapeutic peptide secreted from the intestines following food intake, which stimulates the secretion of insulin from the pancreas. The native GLP-1 has a very short plasma half-life, owning to renal clearance and degradation by the enzyme dipeptidyl peptidase-4. To overcome this issue, various GLP-1 agonists with increased resistance to proteolytic degradation and reduced renal clearance have been developed, with several currently marketed. Strategies, such as controlled release delivery systems, methods to reduce renal clearance (e.g., PEGylation and conjugation to antibodies), and methods to improve proteolytic stability (e.g., stapling, cyclization, and glycosylation) provide means to further improve the ability of GLP-1 analogs. These will be discussed in this literature review.

Type-3c Diabetes Mellitus, Diabetes of Exocrine Pancreas - An Update

BACKGROUND

The incidence of diabetes is increasing steeply; the number of diabetics has doubled over the past three decades. Surprisingly, the knowledge of type 3c diabetes mellitus (T3cDM) is still unclear to the researchers, scientist and medical practitioners, leading towards erroneous diagnosis, which is sometimes misdiagnosed as type 1 diabetes mellitus (T1DM), or more frequently type 2 diabetes mellitus (T2DM). This review is aimed to outline recent information on the etiology, pathophysiology, diagnostic procedures, and therapeutic management of T3cDM patients.

METHODS

The literature related to T3cDM was thoroughly searched from the public domains and reviewed extensively to construct this article. Further, existing literature related to the other forms of diabetes is reviewed for projecting the differences among the different forms of diabetes. Detailed and updated information related to epidemiological evidence, risk factors, symptoms, diagnosis, pathogenesis and management is structured in this review.

RESULTS

T3cDM is often misdiagnosed as T2DM due to the insufficient knowledge differentiating between T2DM and T3cDM. The pathogenesis of T3cDM is explained which is often linked to the history of chronic pancreatitis, pancreatic cancer. Inflammation, and fibrosis in pancreatic tissue lead to damage both endocrine and exocrine functions, thus leading to insulin/glucagon insufficiency and pancreatic enzyme deficiency.

CONCLUSION

Future advancements should be accompanied by the establishment of a quick diagnostic tool through the understanding of potential biomarkers of the disease and newer treatments for better control of the diseased condition.

Determinants of Fasting Hyperglucagonemia in Patients with Type 2 Diabetes and Nondiabetic Control Subjects

BACKGROUND

Fasting hyperglucagonemia can be detrimental to glucose metabolism in patients with type 2 diabetes (T2D) and may contribute to metabolic disturbances in obese and/or prediabetic subjects. However, the mechanisms underlying fasting hyperglucagonemia remain elusive.

METHODS

We evaluated the interrelationship between fasting hyperglucagonemia and demographic and biochemical parameters in 106 patients with T2D (31% female, age: 57 ± 9 years [mean ± standard deviation; body mass index (BMI): 30.1 ± 4.4 kg/m²; fasting plasma glucose (FPG): 9.61 ± 2.39 mM; hemoglobin A1c (HbA1c): 57.1 ± 13.1 mmol/mol] and 163 nondiabetic control subjects (29% female; age: 45 ± 17 years; BMI: 25.8 ± 4.1 kg/m²; FPG: 5.2 ± 0.4 mM; and HbA1c: 35.4 ± 3.8 mmol/mol). Multiple linear regression analysis was applied using a stepwise approach with fasting plasma glucagon as dependent parameter and BMI, waist-to-hip ratio (WHR), blood pressure, hemoglobin A1c, FPG, and insulin concentrations as independent parameters.

RESULTS

Fasting plasma glucagon concentrations were significantly higher among patients with T2D (13.5 ± 6.3 vs. 8.5 ± 3.8 mM, P < 0.001) together with HbA1c (P < 0.001), FPG (P < 0.001), and insulin (84.9 ± 56.4 vs. 57.7 ± 35.3 mM, P < 0.001). When adjusted for T2D, HbA1c and insulin were significantly positive determinants for fasting plasma glucagon concentrations. Furthermore, WHR comprised a significant positive determinant.

CONCLUSIONS

We confirm that fasting plasma glucagon concentrations are abnormally high in patients with T2D, and show that fasting plasma glucagon concentrations are influenced by WHR (in addition to glycemic control and fasting plasma insulin concentrations), which may point to visceral fat deposition as an important determinant of increased fasting plasma glucagon concentrations.

Glucose homeostasis dependency on acini-islet-acinar (AIA) axis communication: a new possible pathophysiological hypothesis regarding diabetes mellitus

Studies have highlighted the existence of two intra-pancreatic axes of communication: one involved in the regulation of enzyme production by insulin-the insular-acinar axis; and another involved in the regulation of insulin release by pancreatic enzymes-the acini-insular axis. Previous studies by our laboratory show that pancreatic enzymes can affect blood glucose homeostasis and insulin secretion independently of their digestive functions, both from the gut lumen and probably from the blood. As a result we would like to introduce here the concept of acini-islet-acinar (AIA) axis communication (feedback), which could play an important role in the development of obesity and diabetes type 2. The AIA feedback links the endocrine and exocrine parts of the pancreas and emphasizes the essential role that the pancreas plays, as a single organ, in the regulation of glucose homeostasis by amylase most probably in gut epithelium and by insulin and glucagon in peripheral blood.

Effect of Frey's procedure on islet cell function in patients with chronic calcific pancreatitis

BACKGROUND

Frey's procedure involves both drainage and resection of the pancreas in subjects with chronic calcific pancreatitis (CCP). The procedure may affect the pancreatic endocrine function after surgery. The present study was to evaluate the effect of Frey's procedure on both beta and alpha cell function in CCP patients.

METHODS

Thirty CCP patients who underwent Frey's procedure were included. According to the glycemic status, patients were divided into the diabetes mellitus (DM), prediabetes, and normal glucose tolerance (NGT) groups. Islet cell function was assessed before and 3 months after surgery.

RESULTS

At baseline, there was a significant difference in beta cell function among the three groups [NGT group 1.71 (1.64-2.07) vs prediabetes group1.50 (0.83-1.61) vs DM group 0.33 (0.12-0.55), P < 0.0001], but the insulin resistance was not different among them. Post glucose hyperglucagonemia representing alpha-cell dysfunction during oral glucose tolerance test was present in all of them, but showed no significant difference [NGT group 0.15 (0.06-0.31) vs prediabetes group 0.32 (0.05-0.70) vs DM group 0.07 (0.02-0.18), P = 0.20]. Frey's procedure did not change beta cell function and insulin resistance. However, alpha-cell dysfunction deteriorated after surgery [0.10 (0.03-0.27) vs 0.33 (0.09-0.68), P = 0.004].

CONCLUSIONS

Although Frey's procedure does not affect the beta cell function and insulin resistance in CCP patients, the alpha-cell dysfunction deteriorates after surgery.

Chronic pancreatitis: review and update of etiology, risk factors, and management

Chronic pancreatitis is a syndrome involving inflammation, fibrosis, and loss of acinar and islet cells which can manifest in unrelenting abdominal pain, malnutrition, and exocrine and endocrine insufficiency. The Toxic-Metabolic, Idiopathic, Genetic, Autoimmune, Recurrent and Severe Acute Pancreatitis, Obstructive (TIGAR-O) classification system categorizes known causes and factors that contribute to chronic pancreatitis. Although determining disease etiology provides a framework for focused and specific treatments, chronic pancreatitis remains a challenging condition to treat owing to the often refractory, centrally mediated pain and the lack of consensus regarding when endoscopic therapy and surgery are indicated. Further complications incurred include both exocrine and endocrine pancreatic insufficiency, pseudocyst formation, bile duct obstruction, and pancreatic cancer. Medical treatment of chronic pancreatitis involves controlling pain, addressing malnutrition via the treatment of vitamin and mineral deficiencies and recognizing the risk of osteoporosis, and administering appropriate pancreatic enzyme supplementation and diabetic agents. Cornerstones in treatment include the recognition of pancreatic exocrine insufficiency and administration of pancreatic enzyme replacement therapy, support to cease smoking and alcohol consumption, consultation with a dietitian, and a systematic follow-up to assure optimal treatment effect.

Gastrointestinal Symptoms in Diabetes: Prevalence, Assessment, Pathogenesis, and Management

If you haven't measured something, you really don't know much about it.-Karl Pearson (attributed)Gastrointestinal (GI) symptoms represent an important and often unappreciated cause of morbidity in diabetes, although the significance of this burden across the spectrum of patients and the underlying pathophysiology, including the relationship of symptoms with glycemic control, remain poorly defined. The relevance of GI symptoms and the necessity for their accurate assessment have increased with the greater focus on the gut as a therapeutic target for glucose lowering. This review addresses the prevalence, assessment, pathogenesis, and management of GI symptoms in diabetes, beginning with broad principles and then focusing on specific segments of the GI tract. We initially performed a literature search of PubMed by using synonyms and combinations of the following search terms: "gastrointestinal symptoms", "diabetes", "prevalence", "pathogenesis", "diagnosis", and "management". We restricted the search results to English only. Review papers and meta-analyses are presented as the highest level of evidence where possible followed by randomized controlled trials, uncontrolled trials, retrospective and observational data, and expert opinion.

Metabolic markers of protein maldigestion after a 15N test meal in minipigs with pancreatic exocrine insufficiency

The effect of pancreatic exocrine insufficiency (PEI) on protein malabsorption is little documented, partly due to methodological barriers. We aimed to validate biomarkers of protein malabsorption using a ¹⁵N test meal in a minipig model of PEI. Six pancreatic duct-ligated minipigs were used as a model of PEI and four nonoperated animals as a control. All animals were equipped with an ileocecal reentrant cannula. Minipigs were given a test meal containing [¹⁵N]casein. The PEI animals repeated the test three times, in the absence of any pancreatic enzymes, or after pancreatic substitution at two levels [ A or B: 7,500 or 75,000 (lipase) and 388 or 3881 (protease) FIP U]. Ileal chyme, urine, and blood were collected postprandially. Nitrogen and ¹⁵N were measured in digestive and metabolic pools. We obtained a gradient of ileal protein digestibility from 29 ± 11% in PEI to 89 ± 6% in the controls and a dose- dependent response of enzymes. Insulin and gastric inhibitory polypeptide secretions were decreased by PEI, an effect that was counteracted with the enzymes at level B. The total recovery of ¹⁵N in urinary urea and plasma proteins was 14 ± 5.1% in the control group and decreased to 5.5 ± 2.1% by PEI. It was dose dependently restored by the treatment. Both ¹⁵N recovery in plasma and urine were correlated to protein digestibility. We confirm that the ¹⁵N transfer in those pools is a sensitive marker of protein malabsorption. Nevertheless, an optimization of the test meal conditions would be necessary in the view of implementing a clinical test. NEW & NOTEWORTHY We designed an intervention study to create a gradient of ileal protein digestibility in minipigs with pancreatic exocrine insufficiency and to validate reliable metabolic markers using a ¹⁵N oral meal test. ¹⁵N recovery in plasma proteins and to a higher extent in urine was sensitive to protein malabsorption. This test is minimally invasive and could be used to reveal protein malabsorption in patients.

Targeted intestinal delivery of incretin secretagogues-towards new diabetes and obesity therapies

A new strategy under development for the treatment of type 2 diabetes and obesity is to mimic some of the effects of bariatric surgery by delivering food-related stimuli to the distal gastrointestinal tract where they should enhance the release of gut hormones such as glucagon-like peptide-1 (GLP-1) and peptideYY (PYY). Methods include inhibition of food digestion and absorption in the upper GI tract, or oral delivery of stimuli in capsules or pelleted form to protect them against gastric degradation. A variety of agents have been tested in humans using capsules, microcapsules or pellets, delivering nutrients, bile acids, fatty acids and bitter compounds. This review examines the outcomes of these different approaches and supporting evidence from intestinal perfusion studies.

Glucose-Dependent Insulinotropic Polypeptide (GIP) Inhibits Bone Resorption Independently of Insulin and Glycemia

CONTEXT

The gut hormone glucose-dependent insulinotropic polypeptide (GIP) causes postprandial insulin release and inhibits bone resorption assessed by carboxy-terminal collagen crosslinks (CTX).

OBJECTIVE

To study if GIP affects bone homeostasis biomarkers independently of insulin release and glycemic level.

DESIGN

Randomized, double-blinded, crossover study with 5 study days.

PATIENTS

Ten male C-peptide-negative patients with type 1 diabetes.

INTERVENTIONS

On 3 matched days with "low glycemia" (plasma glucose in the interval 3 to 7 mmol/L for 120 minutes), we administered intravenous (IV) GIP (4 pmol × kg-1 × min-1), glucagon-like peptide 1 (1 pmol × kg-1 × min-1), or placebo (saline), and on 2 matched days with "high glycemia" (plasma glucose 12 mmol/L for 90 minutes), we administered either GIP or saline.

MAIN OUTCOME MEASURES

CTX, procollagen type 1 N-terminal propeptide (P1NP), and parathyroid hormone (PTH).

RESULTS

During low glycemia: GIP progressively suppressed CTX from baseline by up to 59 ± 18% compared with 24 ± 10% during saline infusion (P < 0.0001). Absolute values of P1NP and PTH did not differ between days. During high glycemia: GIP suppressed CTX from baseline by up to 59 ± 19% compared with 7 ± 9% during saline infusion (P < 0.0001). P1NP did not differ between days. GIP suppressed PTH after 60 minutes compared with saline (P < 0.01), but this difference disappeared after 90 minutes.

CONCLUSIONS

Short-term GIP infusions robustly reduce bone resorption independently of endogenous insulin secretion and during both elevated and low plasma glucose, but have no effect on P1NP or PTH after 90 minutes.

Evaluation of a Mixed Meal Test for Diagnosis and Characterization of PancrEaTogEniC DiabeTes Secondary to Pancreatic Cancer and Chronic Pancreatitis: Rationale and Methodology for the DETECT Study From the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer

Pancreatogenic diabetes mellitus is most commonly the result of chronic pancreatitis but can also occur secondary to pancreatic cancer. The early identification of pancreatogenic diabetes and distinction from the more prevalent type 2 diabetes are clinically significant; however, currently, there is no validated method to differentiate these diabetes subtypes. We describe a study, "Evaluation of a Mixed Meal Test for Diagnosis and Characterization of PancrEaTogEniC DiabeTes Secondary to Pancreatic Cancer and Chronic Pancreatitis: the DETECT study," that seeks to address this knowledge gap. The DETECT study is a multicenter study that will examine differences in hormone and glucose excursions after a mixed meal test. The study will also create a biorepository that will be used to evaluate novel diagnostic biomarkers for differentiating these diabetes subtypes.

Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1

An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.

Less common etiologies of exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI), an important cause of maldigestion and malabsorption, results from primary pancreatic diseases or secondarily impaired exocrine pancreatic function. Besides cystic fibrosis and chronic pancreatitis, the most common etiologies of EPI, other causes of EPI include unresectable pancreatic cancer, metabolic diseases (diabetes); impaired hormonal stimulation of exocrine pancreatic secretion by cholecystokinin (CCK); celiac or inflammatory bowel disease (IBD) due to loss of intestinal brush border proteins; and gastrointestinal surgery (asynchrony between motor and secretory functions, impaired enteropancreatic feedback, and inadequate mixing of pancreatic secretions with food). This paper reviews such conditions that have less straightforward associations with EPI and examines the role of pancreatic enzyme replacement therapy (PERT). Relevant literature was identified by database searches. Most patients with inoperable pancreatic cancer develop EPI (66%-92%). EPI occurs in patients with type 1 (26%-57%) or type 2 diabetes (20%-36%) and is typically mild to moderate; by definition, all patients with type 3c (pancreatogenic) diabetes have EPI. EPI occurs in untreated celiac disease (4%-80%), but typically resolves on a gluten-free diet. EPI manifests in patients with IBD (14%-74%) and up to 100% of gastrointestinal surgery patients (47%-100%; dependent on surgical site). With the paucity of published studies on PERT use for these conditions, recommendations for or against PERT use remain ambiguous. The authors conclude that there is an urgent need to conduct robust clinical studies to understand the validity and nature of associations between EPI and medical conditions beyond those with proven mechanisms, and examine the potential role for PERT.

Chronic Pancreatitis in the 21st Century - Research Challenges and Opportunities: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

A workshop was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases to focus on research gaps and opportunities in chronic pancreatitis (CP) and its sequelae. This conference marked the 20th year anniversary of the discovery of the cationic trypsinogen (PRSS1) gene mutation for hereditary pancreatitis. The event was held on July 27, 2016, and structured into 4 sessions: (1) pathophysiology, (2) exocrine complications, (3) endocrine complications, and (4) pain. The current state of knowledge was reviewed; many knowledge gaps and research needs were identified that require further investigation. Common themes included the need to design better tools to diagnose CP and its sequelae early and reliably, identify predisposing risk factors for disease progression, develop standardized protocols to distinguish type 3c diabetes mellitus from other types of diabetes, and design effective therapeutic strategies through novel cell culture technologies, animal models mimicking human disease, and pain management tools. Gene therapy and cystic fibrosis conductance regulator potentiators as possible treatments of CP were discussed. Importantly, the need for CP end points and intermediate targets for future drug trials was emphasized.

Type 3c (pancreatogenic) diabetes mellitus secondary to chronic pancreatitis and pancreatic cancer

Diabetes mellitus is a group of diseases defined by persistent hyperglycaemia. Type 2 diabetes, the most prevalent form, is characterised initially by impaired insulin sensitivity and subsequently by an inadequate compensatory insulin response. Diabetes can also develop as a direct consequence of other diseases, including diseases of the exocrine pancreas. Historically, diabetes due to diseases of the exocrine pancreas was described as pancreatogenic or pancreatogenous diabetes mellitus, but recent literature refers to it as type 3c diabetes. It is important to note that type 3c diabetes is not a single entity; it occurs because of a variety of exocrine pancreatic diseases with varying mechanisms of hyperglycaemia. The most commonly identified causes of type 3c diabetes are chronic pancreatitis, pancreatic ductal adenocarcinoma, haemochromatosis, cystic fibrosis, and previous pancreatic surgery. In this Review, we discuss the epidemiology, pathogenesis, and clinical relevance of type 3c diabetes secondary to chronic pancreatitis and pancreatic ductal adenocarcinoma, and highlight several important knowledge gaps.

Anesthetic Propofol-Induced Gene Expression Changes in Patients Undergoing Coronary Artery Bypass Graft Surgery Based on Dynamical Differential Coexpression Network Analysis

We aimed to determine the influence of anesthetic propofol on gene expression in patients treated by coronary artery bypass graft (CABG) surgery based on differential coexpression network (DCN) and to further reveal the novel mechanisms of the cardioprotective effects of propofol. Firstly, we constructed the DCN for disease condition based on Pearson correlation coefficient (PCC) and weight value. Secondly, the inference of modules was applied to search modules from DCN with same members but varied connectivity. Furthermore, we measured the statistical significance of the modules for selecting differential modules (DMs). Finally, attract method was used for DMs analysis to select key modules. Based on the δ value, 11928 edges and 2956 nodes were chosen to construct DCNs. A total of 29 seed genes were selected. Moreover, by quantifying connectivity changes in shared gene modules across different conditions, 8 DMs with higher connectivity dynamics were identified. Then, we extracted key modules using attract method, there were 8 key modules, and the top 3 modules were module 1, 2, and 3. Furthermore, GCG, PPY, and PON1 were initial seed genes of these 3 key modules, respectively. Accordingly, GCG and PON1 might exert important roles in the cardioprotective effects of propofol during CABG.

The nutritional management of type 3c (pancreatogenic) diabetes in chronic pancreatitis

Type 3c diabetes mellitus (T3cDM), also known as pancreatogenic diabetes, refers to diabetes caused by disease of the exocrine pancreas. T3cDM is not commonly recognised by clinicians and frequently it is misclassified as T1DM, or more commonly, T2DM. T3cDM can be difficult to distinguish from T1DM and T2DM, and it often co-exists with the latter. The aim of this review is to describe T3cDM, along with its complications, diagnosis and management. We focus on the nutritional implications of T3cDM for those with chronic pancreatitis, and provide a practical guide to the nutritional management of this condition.

Risk Factors for Diabetes Mellitus in Chronic Pancreatitis: A Cohort of 2,011 Patients

Diabetes mellitus (DM) is a common complication of chronic pancreatitis (CP) and increases the mortality. The identification of risk factors for DM development may contribute to the early detection and potential risk reduction of DM in patients with CP.Patients with CP admitted to Changhai Hospital (Shanghai, China) from January 2000 to December 2013 were enrolled. Cumulative rates of DM after the onset of CP were calculated by Kaplan-Meier method. Risk factors for DM development after the diagnosis of CP were identified by Cox proportional hazards regression model.A total of 2011 patients with CP were enrolled. During follow-up (median duration, 22.0 years), 564 patients developed DM. Cumulative rates of DM 20 and 50 years after the onset of CP were 45.8% (95% confidence interval [CI], 41.8%-50.0%) and 90.0% (95% CI, 75.4%-97.7%), respectively. Five risk factors for DM development after the diagnosis of CP were identified: male sex (hazard ratio [HR], 1.51; 95% CI, 1.08-2.11), alcohol abuse (HR, 2.00; 95% CI, 1.43-2.79), steatorrhea (HR, 1.46; 95% CI, 1.01-2.11), biliary stricture (HR, 2.25; 95% CI, 1.43-3.52), and distal pancreatectomy (HR, 3.41; 95% CI, 1.80-6.44).In conclusion, the risk of developing DM in patients with CP is not only influenced by the development of biliary stricture and steatorrhea indicating disease progression, and inherent nature of study subjects such as male sex, but also by modifiable factors including alcohol abuse and distal pancreatectomy.

Early Alterations in Glycemic Control and Pancreatic Endocrine Function in Nondiabetic Patients With Chronic Pancreatitis

OBJECTIVES

Diabetes mellitus is a frequent consequence of chronic pancreatitis (CP). Little is known about pancreatic endocrine function before the development of diabetes mellitus in CP, particularly in females, or those without calcific and/or alcoholic pancreatitis.

METHODS

Twenty-five nondiabetic adult patients with CP (19 female; mean [SE] age, 34.2 [2.4] years) were compared with 25 healthy controls matched for age, sex, and body mass index. Subjects underwent frequent sample intravenous glucose tolerance testing (FSIVGTT) and mixed meal tolerance testing (MMTT).

RESULTS

Mean (SE) fasting glucose was higher in patients with CP (89.5 [2.3] mg/dL) than in controls (84.4 [1.2] mg/dL, P = 0.04). On MMTT, patients with CP had a higher area under the curve (AUC) glucose and AUC glucagon compared with controls (P ≤ 0.01). The AUC C-peptide was equivalent (P = 0.6) but stimulated C-peptide at 30 minutes was lower in patients with CP (P = 0.04). Mean insulin sensitivity index calculated from the FSIVGTT was lower in CP group, indicating reduced insulin sensitivity (P ≤ 0.01). Disposition index (insulin secretion adjusted for insulin sensitivity on FSIVGTT) was lower in patients with CP (P = 0.01).

CONCLUSIONS

Patients with CP had higher fasting and MMTT glucose levels, without a compensatory increase in insulin secretion suggesting subtle early islet dysfunction. Our cohort had relative hyperglucagonemia and was less insulin sensitive than controls.

GLP1- and GIP-producing cells rarely overlap and differ by bombesin receptor-2 expression and responsiveness

The incretin hormones glucagon-like peptide-1 (GLP1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from intestinal endocrine cells, the so-called L- and K-cells. The cells are derived from a common precursor and are highly related, and co-expression of the two hormones in so-called L/K-cells has been reported. To investigate the relationship between the GLP1- and GIP-producing cells more closely, we generated a transgenic mouse model expressing a fluorescent marker in GIP-positive cells. In combination with a mouse strain with fluorescent GLP1 cells, we were able to estimate the overlap between the two cell types. Furthermore, we used primary cultured intestinal cells and isolated perfused mouse intestine to measure the secretion of GIP and GLP1 in response to different stimuli. Overlapping GLP1 and GIP cells were rare (∼5%). KCl, glucose and forskolin+IBMX increased the secretion of both GLP1 and GIP, whereas bombesin/neuromedin C only stimulated GLP1 secretion. Expression analysis showed high expression of the bombesin 2 receptor in GLP1 positive cells, but no expression in GIP-positive cells. These data indicate both expressional and functional differences between the GLP1-producing 'L-cell' and the GIP-producing 'K-cell'.