High fat diet and GLP-1 drugs induce pancreatic injury in mice

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Abstract

Glucagon Like Peptide-1 (GLP-1) drugs are currently used to treat type-2 diabetes. Safety concerns for increased risk of pancreatitis and pancreatic ductal metaplasia have accompanied these drugs. High fat diet (HFD) is a type-2 diabetes risk factor that may affect the response to GLP-1 drug treatment. The objective of the present study was to investigate the effects of diet and GLP-1 based drugs on the exocrine pancreas in mice. Experiments were designed in a mouse model of insulin resistance created by feeding a HFD or standard diet (STD) for 6 weeks. The GLP-1 drugs, sitagliptin (SIT) and exenatide (EXE) were administered once daily for additional 6 weeks in both mice fed HFD or STD. The results showed that body weight, blood glucose levels, and serum levels of pro-inflammatory cytokines (TNFα, IL-1β, and KC) were significantly greater in HFD mice than in STD mice regardless of GLP-1 drug treatment. The semi-quantitative grading showed that pancreatic changes were significantly greater in EXE and SIT-treated mice compared to control and that HFD exacerbated spontaneous exocrine pancreatic changes seen in saline-treated mice on a standard diet. Exocrine pancreatic changes identified in this study included acinar cell injury (hypertrophy, autophagy, apoptosis, necrosis, and atrophy), vascular injury, interstitial edema and inflammation, fat necrosis, and duct changes. These findings support HFD as a risk factor to increased susceptibility/severity for acute pancreatitis and indicate that GLP-1 drugs cause pancreatic injury that can be exacerbated in a HFD environment.

Introduction

A number of drugs marketed for treatment of type-2 diabetes are active in the glucagon-like-peptide-1 (GLP-1) receptor signaling pathway. These GLP-1 based drugs function as either GLP-1 receptor agonists, (i.e., FDA approved exenatide (EXE) and liraglutide, and drugs still undergoing critical trials: lixisenatide, and albiglutide) or dipeptidyl-peptidase-4 (DPP-4) inhibitors (i.e., FDA approved sitagliptin (SIT), vildagliptin, saxagliptin, and linagliptin). In homeostasis, GLP-1 binds the GLP-1 receptor initiating signaling that increases cyclic-AMP (cAMP) and up-regulates pathways, primarily phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt), resulting in increased production and cellular uptake of insulin thereby lowering blood glucose (Marathe et al., 2013, Perry and Greig, 2003). Under normal physiological conditions, GLP-1 is rapidly degraded by DPP-4. Therapeutically, DPP-4 inhibitors allow prolonged survival of GLP-1 and potentiate the effects of GLP-1 receptor signaling. The efficacy of DPP-4 inhibitors is slightly lower than GLP-1 agonists because DDP-4 inhibitors produce a relatively modest increase in postpradial levels of intact GLP-1 and have minimal effects on the rate of gastric emptying (Marathe et al., 2013).

Safety concerns surrounding several GLP-1 based drugs have surfaced repeatedly in postmarketing surveillance of these drugs in those with type-2 diabetes mellitus. Thirty cases of EXE-associated pancreatitis were reported to FDA's Adverse Event Reporting System in 2005–2006 (Ahmad and Swann, 2008). Eighty-eight cases of acute pancreatitis associated with SIT were also reported to the FDA in 2006–2009 (U.S. FDA, 2009). Published case reports and epidemiology studies have also suggested that treatment of type-2 diabetes with EXE and/or SIT was associated with acute pancreatitis (Anderson and Trujillo, 2010, Ayoub et al., 2010, Denker and Dimarco, 2006, Elashoff et al., 2011, Garg et al., 2010a, Garg et al., 2010b, Iyer et al., 2012, Singh et al., 2013, Tripathy et al., 2008). Recently a pathological, immunohistochemical, and morphometric study using human pancreatic sections demonstrated that treatment of type-2 diabetes with EXE or SIT markedly increases the gross pancreatic size with cellular proliferation and dysplasia (Butler et al., 2013). However, a body of preclinical and clinical data also exists that indicates no association of GLP-1 drugs with pancreatic injury (Dore et al., 2011, Garg et al., 2010a, Romley et al., 2012, Vrang et al., 2012).

High fat and high carbohydrate diets, not uncommon in many human populations, could be one contributor to increased susceptibility. Elevated blood triglyceride is usually recognized as a risk factor for clinical acute pancreatitis (Tsuang et al., 2009), as are hyperlipidemia (Cameron et al., 1972, Yadav and Pitchumoni, 2003) and obesity. A high fat diet can produce a degree of insulin resistance in animal models and can lead to fatty infiltration in the pancreas. With anti-diabetic drug treatment, C57BL/6 mice (Fernandes-Santos et al., 2009) and amylin-expressing transgenic rats (Matveyenko et al., 2009) both demonstrated fatty infiltration in the pancreas that was associated with morphological changes of pancreatitis. More recently it has been demonstrated that high fat diet (HFD) in mice models can lead to obesity, metabolic disturbances, and pancreatic inflammation (Dawson et al., 2013), and can also activate oncogenic Kras via Cox2, leading to pancreatic inflammation and fibrosis, and development of pancreatic intraepithelial neoplasia and pancreatic ductal adenocarcinoma (Philip et al., 2013).

The objectives of the present study in a mouse model were 1) to determine whether or not EXE and SIT induce acute pancreatitis; 2) to determine whether or not HFD affects the exocrine pancreas; 3) to detect HFD and GLP-1 influences on the pro-inflammatory cytokine profile; 4) to characterize pathological changes of exocrine pancreatic injury and to explore possible pathogenesis.

Section snippets

Animals

Male C57BL/6 mice 6 to 8 weeks of age were purchased from Harlan Laboratories (Fredrick, MD). Mice were housed individually in an environmentally controlled room (18 °C–21 °C, 40%–70% relative humidity) with a twelve-hour light/dark cycle. Mice were initially fed Certified Purina Rodent Chow #5002 (Ralston Purina Co., St. Louis, MO) providing 63% of calories through carbohydrates, 24% from protein, and 13% from fat. Per the experimental design, some mice were subsequently placed on a Teklad Custom

Results

At termination, body weight and blood glucose levels were significantly greater in mice on HFD compared to mice on STD regardless of drug treatment (Fig. 2). Mice on HFD also exhibited higher levels of specific pro-inflammatory cytokines (TNFα, IL-1β, and KC). Serum levels of IL-1β were also significantly influenced by SIT treatment in HFD mice (Fig. 2). However, the serum levels of IL-10, IL-12p70 and IFNγ were not significantly elevated by diet or drug treatment (data not shown).

Discussion

Acute pancreatitis is an inflammatory process of the exocrine pancreas secondary to pancreatic tissue injury and necrosis (Gukovskaya and Gukovsky, 2012, Kloppel and Maillet, 1998). Pancreatic inflammation and cell death are critical to the evolution of acute pancreatitis from pancreatic injury (Gukovsky et al., 1998). Several studies in animal models have shown that experimental acute pancreatitis begins within acinar cells and is initiated by intracellular zymogen activation attributed to

Conclusion

This study implicates the GLP-1 drugs, exenatide and sitagliptin, in pancreatic injury in a mouse model. Study of cytokine and histopathology data support independent exacerbation of pancreatic injury by GLP-1 drugs and by a high fat diet that could be either additive or synergistic when both variables are present. The present study implies that high fat diet, as a risk factor, can enhance the susceptibility to and/or the severity of inadvertent pharmacologic initiation of acute pancreatitis by

Conflict of interest statement

The authors have no conflicts of interest or financial disclosures.

References (60)

  • D. Mozaffarian et al.

    Dietary intake of trans fatty acids and systemic inflammation in women

    Am. J. Clin. Nutr.

    (2004)
  • C.J. Nitsche et al.

    Drug induced pancreatitis

    Best Pract. Res. Clin. Gastroenterol.

    (2010)
  • T. Perry et al.

    The glucagon-like peptides: a double-edged therapeutic sword?

    Trends Pharmacol. Sci.

    (2003)
  • M. Yan et al.

    Long-term high-fat diet induces pancreatic injuries via pancreatic microcirculatory disturbances and oxidative stress in rats with hyperlipidemia

    Biochem. Biophys. Res. Commun.

    (2006)
  • S.R. Ahmad et al.

    Exenaride and rare adverse events

    N. Engl. J. Med.

    (2008)
  • S.L. Anderson et al.

    Association of panreatitis with glucagon-like peptide-1 agonist use

    Ann. Pharmacother.

    (2010)
  • A.K. Banerjee et al.

    Drug-induced acute pancreatitis. A critical review

    Med. Toxicol. Adverse Drug Exp.

    (1989)
  • S.G. Barreto et al.

    Drug-induced acute pancreatitis in a cohort of 328 patients. A single-center experience from Australia

    J. Pancreas

    (2011)
  • J. Bastard et al.

    Recent advances in the relationship between obesity, inflammation, and insulin resistance

    Eur. Cytokine Netw.

    (2006)
  • M.O. Blackstone

    Hypothesis: vascular compromise is the central pathogenicmechanism for acute hemorrhagic pancreatitis

    Perspect. Biol. Med.

    (1995)
  • M.W. Buchler et al.

    Acute pancreatitis

  • A.E. Butler et al.

    Marked expansion of exocrine and endocrine pancreas with incretin therapy I n human with increased exeocrine pancreas dysplasia and the potential for glucagon-producing neuroendocrine tumors

    Diabetes

    (2013)
  • J. Cameron et al.

    Acute pancreatitis with hyperlipemia: the incidence of lipid abnormalities in acute pancreatitis

    Ann. Surg.

    (1972)
  • P. Chowdhury et al.

    Response of rat exocrine pancreas to high-fat and high-carbohydrate diets

    Proc. Soc. Exp. Biol. Med.

    (2000)
  • D.W. Dawson et al.

    High fat, high calorie diet promotes early pancreatic neoplasia in the conditional KrasG12D mouse model

    Cancer Prev. Res.

    (2013)
  • P.S. Denker et al.

    Exenatide (exendin-4)-induced pancreatitis: a case report

    Diabetes Care

    (2006)
  • D.D. Dore et al.

    A cohort study of acute pancreatitis in relation to exenatide use

    Diabetes Obes. Metab.

    (2011)
  • C. Fernandes-Santos et al.

    Rosiglitazone aggravates nonalcoholic fatty pancreatic disease in C57BL/6 mice fed high-fat and high-sucrose diet

    Pancreas

    (2009)
  • W.E. Fisher et al.

    ePancreas

  • R. Garg et al.

    Pancreatitis associated with the use of sitagliptin and orlistat combination: a case report

    Diabet. Med.

    (2010)
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