Galantamine ameliorates experimental pancreatitis

Abstract

Background: Acute pancreatitis is a common and serious inflammatory condition currently lacking disease modifying therapy. The cholinergic anti-inflammatory pathway (CAP) is a potent protective anti-inflammatory response activated by vagus nerve-dependent α7 nicotinic acetylcholine receptor (α7nAChR) signaling using splenic CD4⁺ T cells as an intermediate. Activating the CAP ameliorates experimental acute pancreatitis. Galantamine is an acetylcholinesterase inhibitor (AChEI) which amplifies the CAP via modulation of central muscarinic ACh receptors (mAChRs). However, as mAChRs also activate pancreatitis, it is currently unknown whether galantamine would be beneficial in acute pancreatitis.

Methods: The effect of galantamine (1-6 mg/kg-body weight) on caerulein-induced acute pancreatitis was evaluated in mice. Two hours following 6 hourly doses of caerulein (50 µg/kg-body weight), organ and serum analyses were performed with accompanying pancreatic histology. Experiments utilizing vagotomy, gene knock out (KO) technology and the use of nAChR antagonists were also performed.

Results: Galantamine attenuated pancreatic histologic injury which was mirrored by a reduction in serum amylase and pancreatic inflammatory cytokines and an increase the anti-inflammatory cytokine IL-10 in the serum. These beneficial effects were not altered by bilateral subdiaphragmatic vagotomy, KO of either choline acetyltransferase⁺ T cells or α7nAChR, or administration of the nAChR ganglionic blocker mecamylamine or the more selective α7nAChR antagonist methyllycaconitine.

Conclusion: Galantamine improves acute pancreatitis via a mechanism which does not involve previously established physiological and molecular components of the CAP. As galantamine is an approved drug in widespread clinical use with an excellent safety record, our findings are of interest for further evaluating the potential benefits of this drug in patients with acute pancreatitis.

Keywords: Cholinergic anti-inflammatory pathway; Cytokines; Galantamine; Inflammation; Pancreatitis; Vagus nerve.

Fig. 1

Galantamine improves serum markers of acute pancreatitis severity. A Acute pancreatitis was induced by 6 hourly intraperitoneal injections of 50 µg/kg-bw caerulein. Galantamine (1, 4, or 6 mg/kg-bw), or vehicle, was administered one hour prior to the first injection of caerulein and again after the third injection. Mice were euthanized two hours after the final injection of caerulein. Serum collected at the time of euthanasia demonstrates a dose-dependent B decrease in serum amylase and C increase in IL-10. Data are presented as individual mouse data points with mean ± SEM. One-Way ANOVA with Kruskal–Wallis, *p < 0.05, **p < 0.01, ***p < 0.001, ****p ≤ 0.0001, ns = not significant. n = 6–11

Fig. 2

Administration of Galantamine mitigates the histological severity of acute pancreatitis. A–J Representative images of pancreatic tissue stained with H&E at 4x (left panels) and 20x (right panels). A, B Mice without induction of pancreatitis, C, D pancreatitis and vehicle, E, F pancreatitis and galantamine (1 mg/kg-bw), G, H pancreatitis and galantamine (4 mg/kg-bw), and I, J pancreatitis and galantamine (6 mg/kg-bw). Bar = 200 μm

Fig. 3

Administration of galantamine reduces the histological severity of acute pancreatitis. Histological scoring for (A) edema, (B) acinar necrosis, (C) hemorrhage and fat necrosis, (D) inflammation and perivascular infiltration, and (E) total severity. Data are represented as individual mouse data points with mean ± SEM. One-Way ANOVA with Kruskal–Wallis, *p < 0.05, **p < 0.01, ns = not significant. n = 5–6

Fig. 4

Galantamine decreases pancreatitis severity in a vagus nerve-independent manner. A Mice underwent bilateral, subdiaphragmatic vagotomy, or sham operation, then were allowed to recover for 1 week prior to the induction of pancreatitis. Galantamine administration significantly reduces serum amylase (B) and elevates serum IL-10 (C) in sham and vagotomy animals. Data are represented as individual mouse data points with mean ± SEM. Unpaired t-test, *p < 0.05, **p < 0.01, ns = not significant. n = 8–10

Fig. 5

Choline acetyltransferase expressing T-cells are not required for galantamine-mediated effects in acute pancreatitis. A Breeding strategy for CD4⁺/ChAT^fl/fl mice. Galantamine administration significantly reduces serum amylase (B) and elevates serum IL-10 (C) in CD4⁺/ChAT^fl/fl and littermate controls. Data are represented as individual mouse data points with mean ± SEM. Unpaired t-test, *p < 0.05, ns = not significant. n = 10–11

Fig. 6

Nicotinic acetylcholine receptors are not required for galantamine-mediated amelioration of acute pancreatitis. Galantamine administration significantly reduces serum amylase (A) and elevates serum IL-10 (B) in α7nAChR KO and WT mice. C, D Pre-treatment with nicotinic antagonists, mecamylamine (1 mg/kg-bw) or methyllycaconitine (1 mg/kg-bw) does not alter galantamine-mediated suppression of serum amylase. Data are represented as individual mouse data points with mean ± SEM. Unpaired t-test, *p < 0.05, **p < 0.01, ns = not significant. n = 10–11