Insulin and C-peptide plasma levels in patients with severe chronic pancreatitis and fasting normoglycemia

Mechanisms of Post-Pancreatitis Diabetes Mellitus and Cystic Fibrosis-Related Diabetes: A Review of Preclinical Studies

Anatomical proximity and functional correlations between the exocrine and endocrine pancreas warrant reciprocal effects between the two parts. Inflammatory diseases of the exocrine pancreas, such as acute or chronic pancreatitis, or the presence of cystic fibrosis disrupt endocrine function, resulting in diabetes of the exocrine pancreas. Although novel mechanisms are being increasingly identified, the intra- and intercellular pathways regulating exocrine-endocrine interactions are still not fully understood, making the development of new and more effective therapies difficult. Therefore, this review sought to accumulate current knowledge regarding the pathogenesis of diabetes in acute and chronic pancreatitis, as well as cystic fibrosis.

Serum C-peptide, Total and High Molecular Weight Adiponectin, and Pancreatic Cancer: Do Associations Differ by Smoking?

Background: Studies examining associations between circulating concentrations of C-peptide and total adiponectin, two biomarkers related to obesity and insulin secretion and sensitivity and pancreatic ductal adenocarcinoma (PDA) risk have shown inconsistent results and included limited numbers of smokers.Methods: We examined associations of these biomarkers and high molecular weight (HMW) adiponectin with PDA, overall, and by smoking status. We conducted a pooled nested case-control analysis in 3 cohorts (Prostate, Lung, Colorectal, and Ovarian Cancer Trial, Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, and Cancer Prevention Study-II), with 758 cases (435 current smokers) and 1,052 controls (531 smokers) matched by cohort, age, sex, race, blood draw date and follow-up time. We used conditional logistic regression adjusted for age, smoking, diabetes, and body mass index to calculate ORs and 95% confidence intervals (CI).Results: Circulating C-peptide concentration was not associated with PDA in never or former smokers, but was inversely associated with PDA in current smokers (per SD OR = 0.67; 95% CI, 0.54-0.84; Pinteraction = 0.005). HMW adiponectin was inversely associated with PDA in never smokers (OR = 0.43; 95% CI, 0.23-0.81), not associated in former smokers, and positively associated in smokers (OR = 1.23; 95% CI, 1.04-1.45; Pinteraction = 0.009). Total adiponectin was not associated with PDA in nonsmokers or current smokers.Conclusions: Associations of biomarkers of insulin secretion and sensitivity with PDA differ by smoking status. Smoking-induced pancreatic damage may explain the associations in smokers while mechanisms related to insulin resistance associations in nonsmokers.Impact: Future studies of these biomarkers and PDA should examine results by smoking status. Cancer Epidemiol Biomarkers Prev; 26(6); 914-22. ©2017 AACR.

Chronic Pancreatitis and Diabetes Mellitus

OPINION STATEMENT

Patients with chronic pancreatitis should be screening at least annually for diabetes. Lifestyle modifications remain to be an important part of treatment for diabetic control. Unless contraindicated or not tolerated, metformin can be initiated and continued concurrently with other anti-diabetic agents or insulin. All anti-diabetic agents should be used based on their physiology and adverse effect profiles, along with the metabolic status of patients. Insulin therapy should be initiated without delay for any of the following: symptomatic or overt hyperglycemia, catabolic state secondary to uncontrolled diabetes, history of diabetic ketoacidosis, hospitalization or acute exacerbation of pancreatitis, or hyperglycemia that cannot be otherwise controlled. Dose adjustment should be done conservatively as these patients are more likely to be insulin sensitive and have loss of counter regulatory hormones. Insulin pump and continuous glucose monitoring should be considered early during therapy in selected patients. For patients undergoing total pancreatectomy or extensive partial pancreatectomy, evaluations to determine the eligibilities for islet cell autotransplantation should be considered.

Chronic pancreatitis

PURPOSE OF REVIEW

We review important new clinical observations in chronic pancreatitis reported in 2011.

RECENT FINDINGS

Smoking increases the risk of nongallstone acute pancreatitis and the progression of acute pancreatitis to chronic pancreatitis. Binge drinking during Oktoberfest did not associate with increased hospital admissions for acute pancreatitis. The unfolded protein response is an adaptive mechanism to maintain pancreatic health in response to noxious stimuli such as alcohol. Onset of diabetes mellitus in chronic pancreatitis is likely due to progressive disease rather than individual variables. Insufficient pancreatic enzyme dosing is common for treatment of pancreatic steatorrhea; 90 000 United States Pharmacopeia units of lipase should be given with meals. Surgical drainage provides sustained, superior pain relief compared with endoscopic treatment in patients advanced chronic pancreatitis with a dilated main duct ± pancreatic stones. The central acting gabapentoid pregabalin affords a modest 12% pain reduction in patients with chronic pancreatitis but approximately 30% of patients have significant side effects.

SUMMARY

Patients with nongallstone-related acute pancreatitis or chronic pancreatitis of any cause should cease smoking. Results of this year's investigations further elucidated the pancreatic pathobiology due to alcohol, onset of diabetes mellitus in chronic pancreatitis, and the mechanisms and treatment of neuropathic pain in chronic pancreatitis.

Reduced pancreatic volume and beta-cell area in patients with chronic pancreatitis

BACKGROUND & AIMS

Chronic pancreatitis (CP) often leads to the development of diabetes. To understand better this pathogenic mechanism, we investigated whether islet cell area and pancreatic volume are reduced in CP patients, islet cell turnover increases in CP patients, and islet cells are less vulnerable to apoptosis than acinar cells.

METHODS

Pancreatic tissues from 43 patients with CP and 27 controls were examined by immunohistochemistry and quantitative morphometry. Pancreas volume was determined using abdominal computed tomography data.

RESULTS

The pancreatic volumes were 64.9 +/- 4.3 cm(3) in CP patients and 82.3 +/- 6.7 cm(3) in controls (P = .035). beta-cell areas were 0.69% +/- 0.08% in CP patients and 0.97% +/- 0.08% in controls (P = .017), whereas alpha-cell areas did not differ between the groups (P = .47). There were no differences in the frequencies of replication among groups of alpha-cells, beta-cells, duct cells, or acinar cells nor were there differences in numbers of apoptotic alpha-cells or beta-cells between CP patients and controls. However, CP patients had an approximately 10-fold increase in numbers of apoptotic acinar cells compared with controls (P < .0001).

CONCLUSIONS

Pancreatic volume was reduced by 21%, and the area comprising beta-cells was reduced by 29% in patients with CP. The lack of increased beta-cells turnover in CP patients, despite an approximately 10-fold increase in the number of apoptotic acinar cells, suggests that the damage to the pancreas is highly specific for the exocrine compartment and affects the endocrine islets to a lesser extent.

Chronic pancreatitis

PURPOSE OF REVIEW

As in our previous reviews, we endeavor to review important new observations in chronic pancreatitis made in the past year. Topics recently reviewed were truncated to accommodate a surge in publications on clinical aspects of chronic pancreatitis, which contained new observations or insights into new or old concepts.

RECENT FINDINGS

Cystic fibrosis carriers have been found to be at increased risk of pancreatitis. Autoimmune pancreatitis may belong to a multiorgan immunoglobulin G4-related autoimmune disease, and the natural history of chronic pancreatitis differs among the etiologies. Diffusion-weighted magnetic resonance imaging improves upon previous methodologies for diagnosing reduced pancreatic exocrine secretion, and fecal elastase-1 has been found to be a poor test for diagnosing pancreatic malabsorption. Visceral hyperalgesia or heightened central pain perception may contribute to pain in chronic pancreatitis. Instruments are evolving to assess quality of life in chronic pancreatitis, and fibrolytic agents have been found to have therapeutic promise.

SUMMARY

Researchers this past year have further characterized genetic, molecular and clinical aspects of chronic pancreatitis. Advancing the understanding of fibrogenesis, mechanisms of exocrine insufficiency, calcification, and pain and continuing development/modification of diagnostic tests should lead to improved prevention, detection and treatment of the condition. More accurate quantification of outcomes is critical for translating potential therapies from bench to bedside.

The circulating hormonal milieu of the endocrine pancreas in healthy individuals, organ donors, and the isolated perfused human pancreas

Although basal circulating levels of individual islet cell hormones have been measured, few studies compared the molar ratios of the major hormones secreted by the endocrine pancreas. This study examined the basal levels of four major islet hormones: insulin, C-peptide (C-P), glucagon (G), and pancreatic polypeptide (PP) in normal subjects, in organ donors with brain death, and in the isolated perfused human pancreas. Basal blood samples were taken from normal, fasted control subjects (NCs). Pancreata were obtained from 17 organ donors (ODs) with donor portal vein (DPV) and radial arterial (DRA) blood samples taken before organ procurement. Single-pass perfusion was performed on the procured pancreata, and after rewarming and equilibration, basal samples were collected from the splenic vein (SV) for 30 min. Radioimmunoassays of insulin, C-P, G, and PP were performed on all samples, and basal levels of all hormones were expressed as a common unit, femtomoles per milliliter. The data suggest that in the basal state, these four major islet hormones circulate in a relatively constant molar ratio. The ratio of the hormones is altered in brain death and with in vitro perfusion of the pancreas. The isolated perfused human pancreas secretes a relatively constant molar ratio of these hormones; however, this ratio is markedly different from the circulating ratio seen in either the NC group or the OD group. We conclude that a relatively constant hormonal milieu is secreted from the normal endocrine pancreas, and this hormonal milieu is altered after brain death and with isolation and perfusion of the human pancreas.

Beta-cell function and insulin sensitivity in tropical calcific pancreatitis from north India

Tropical calcific pancreatitis (TCP) is a variant of chronic pancreatitis, occurring only in developing countries. It frequently leads to diabetes at a young age. To determine the pathogenesis of glucose intolerance, beta-cell function and insulin sensitivity were measured in 11 TCP patients with normal glucose tolerance (TCP-NGT), six TCP patients with mild hyperglycemia [TCP-DM] median fasting plasma glucose, 6.1 mmol/L), and 16 healthy control subjects. The technique of continuous infusion of glucose with model assessment (CIGMA) was used to calculate beta-cell function (%B) and insulin sensitivity (%S), based on plasma glucose and insulin levels achieved after an intravenous infusion of glucose. %S was similar in both groups of TCP patients and controls. In contrast, %B was significantly lower in TCP-DM patients (median, 53; interquartile range, 41 to 62) compared with controls (90; 65 to 143; P < .01) and with TCP-NGT patients (119; 91 to 159; P < .01). TCP-NGT and control subjects had similar beta-cell function. Among patients with TCP, %B negatively correlated with the duration of pancreatitis (r = -.63, P < .05). Our results suggest that patients with TCP develop diabetes due to a diminution in beta-cell function, and that insulin resistance does not play a significant role in its pathogenesis.

Inflammatory islet damage in patients bearing HLA-DR 3 and/or DR 4 haplotypes does not lead to islet autoimmunity

The hypothesis was tested that islet autoimmunity is induced by ongoing islet cell destruction in subjects with susceptibility genes HLA-DR 3 and/or DR 4. Sixty-one patients with confirmed chronic pancreatitis were analysed, 30 of whom expressed HLA-DR 3 and/or DR 4. Electron microscopy studies in 10 patients showed that the inflammatory process also affected islets, as recognisable from islet cell lysis, intrainsular fibrosis and immune cell infiltrates. None of the sera tested contained any of three markers of islet autoimmunity, ICA, IAA or GAD antibodies. A correlation was seen between the loss of exocrine function, as determined by the ALTAB-test, and of beta-cell function, as determined by the C-peptide response to i.v. glucagon. However, there was no preferential loss of beta-cell function in patients with HLA-DR 3 and/or DR 4. We conclude that islet cell destruction occurs during chronic pancreatitis, but does not trigger islet autoimmunity, even in the presence of HLA-DR 3 and/or DR 4.

Exocrine and endocrine functional reserve in the course of chronic pancreatitis as studied by maximal stimulation tests

Thirty patients suffering from chronic alcoholic pancreatitis (18 calcified) were entered into a study of exocrine and endocrine pancreatic function based on two maximal stimulation tests, namely the secretin-cerulein test and the glucagon test with serum assays of C peptide. The glucagon test was also performed in 19 control subjects. In addition, 10 chronic pancreatitis patients and nine controls were subjected to an oral glucose tolerance test (OGTT) with serum insulin determinations. C peptide basal values were decreased only in patients with severe pancreatic exocrine insufficiency (P less than 0.001), while delta C peptide values were also reduced in patients with moderate exocrine insufficiency (P less than 0.001). Lipase output correlated very well with delta C peptide values (P less than 0.001). While serum insulin levels during OGTT and C peptide basal values showed no significant differences between the chronic pancreatitis and control groups, delta C peptide values were significantly reduced in chronic pancreatitis patients (P less than 0.02). Both endocrine and exocrine function are impaired in chronic pancreatitis, as demonstrated by maximal tests, even in early stages of the disease.